# Scientific Calculator in Python using Tkinter

## Introduction

We have created a Scientific Calculator in Python which is a fully functional graphical user interface system that contains everything that IT students and computer-related courses will require for their college projects. The project has the same symbols, operators, and numbers as a regular calculator, however, the user cannot enter a number using their keyboard. Python is a computer language that may be used to do mathematical and scientific calculations.

## Scientific Calculator in Python using Tkinter: Project Overview

We will mostly understand our codes using comments. Now, let’s start.

### Step.1: Importing Libraries and Designing The Buttons

```import tkinter as tk
from math import *

# used to switch between units of rad, and deg
convert_constant = 1
inverse_convert_constant = 1

btn_params = {'padx': 16, 'pady': 1, 'bd': 4, 'fg': 'white', 'bg': 'black', 'font': ('arial', 18), 'width': 2, 'height': 2, 'relief': 'flat', 'activebackground': "black"}```

In the above code sample, we imported the essential libraries, such as Tkinter, as well as all of the widget classes, including the message box module. This framework allows Python programmers to easily develop GUI components by utilizing the widgets included in the Tk toolkit. Math module for solving mathematical equations. I designed the buttons using the button function.

### Step.2: Defining the Functions of the Calculator

```#Functions for the buttons
def fsin(arg):
return sin(arg * convert_constant)

def fcos(arg):
return cos(arg * convert_constant)

def ftan(arg):
return tan(arg * convert_constant)

def arcsin(arg):
return inverse_convert_constant * (asin(arg))

def arccos(arg):
return inverse_convert_constant * (acos(arg))

def arctan(arg):
return inverse_convert_constant * (atan(arg))```

Here we define some functions to implement the Sin, Cos, Tan, Sin-¹, Cos-¹, Tan-¹. To do that we use some predefine python functions such as Sin(), Cos(), Tan(), asin(), acos(), atan().

### Step.3: Creating a Display of Calculator

```# Here are the methods inside class for all the Buttons in the Scientific Calculator.
class Calculator:
def __init__(self, master):
# expression that will be displayed on screen
self.expression = ""
# be used to store data in memory
self.recall = ""
self.sum_up = ""
# create string for text input
self.text_input = tk.StringVar()
self.master = master
# set frame showing inputs and title
top_frame = tk.Frame(master, width=650, height=10,
bd=10, relief='flat', bg='gray')
top_frame.pack(side=tk.TOP)
# set frame showing all buttons
bottom_frame = tk.Frame(
master, width=650, height=470, bd=2, relief='flat', bg='black')
bottom_frame.pack(side=tk.BOTTOM)

# Here is the code for Display of Calculator.
# entry interface for inputs
txt_display = tk.Entry(top_frame, font=('arial', 36), relief='flat', bg='black', fg='white', textvariable=self.text_input, width=60, bd=12, justify='right')
txt_display.pack()

# row 0
# left bracket button
self.btn_left_brack = tk.Button(
bottom_frame, **btn_params, text="(", border=1, command=lambda: self.btn_click('('))
self.btn_left_brack.grid(row=0, column=0)
# right bracket button
self.btn_right_brack = tk.Button(
bottom_frame, **btn_params, text=")", command=lambda: self.btn_click(')'))
self.btn_right_brack.grid(row=0, column=1)
# takes e to some exponent that you insert into the function
self.btn_exp = tk.Button(
bottom_frame, **btn_params, text="exp", command=lambda: self.btn_click('exp('))
self.btn_exp.grid(row=0, column=2)
# constant pi
self.btn_pi = tk.Button(
bottom_frame, **btn_params, text="π", command=lambda: self.btn_click('pi'))
self.btn_pi.grid(row=0, column=3)
# square root
self.btn_sqrt = tk.Button(
bottom_frame, **btn_params, text="sqrt", command=lambda: self.btn_click('sqrt('))
self.btn_sqrt.grid(row=0, column=4)
# clears self.expression
self.btn_clear = tk.Button(
bottom_frame, **btn_params, text="C", command=self.btn_clear_all)
self.btn_clear.grid(row=0, column=5)
# deletes last string input
self.btn_del = tk.Button(
bottom_frame, **btn_params, text="AC", command=self.btn_clear1)
self.btn_del.grid(row=0, column=6)
# inputs a negative sign to the next entry
self.btn_change_sign = tk.Button(
bottom_frame, **btn_params, text="+/-", command=self.change_signs)
self.btn_change_sign.grid(row=0, column=7)
# division
self.btn_div = tk.Button(
bottom_frame, **btn_params, text="/", command=lambda: self.btn_click('/'))
self.btn_div.grid(row=0, column=8)

# row 1
# changes trig function outputs to degrees
self.btn_Deg = tk.Button(bottom_frame, **btn_params, activeforeground='gray', text="Deg", command=self.convert_deg)
self.btn_Deg.grid(row=1, column=0)
# changes trig function outputs to default back to radians
# cubes a value
self.cube = tk.Button(bottom_frame, **btn_params, text=u"x\u00B3", command=lambda: self.btn_click('**3'))
self.cube.grid(row=1, column=2)
# takes the absolute value of an expression
self.btn_abs = tk.Button(
bottom_frame, **btn_params, text="abs", command=lambda: self.btn_click('abs' + '('))
self.btn_abs.grid(row=1, column=3)
# 'memory clear' button. Wipes self.recall to an empty string
self.btn_MC = tk.Button(
bottom_frame, **btn_params, text="MC", command=self.memory_clear)
self.btn_MC.grid(row=1, column=4)
# seven
self.btn_7 = tk.Button(bottom_frame, **btn_params, text="7", command=lambda: self.btn_click(7))
self.btn_7.configure(activebackground="black", bg='black')
self.btn_7.grid(row=1, column=5)
# eight
self.btn_8 = tk.Button(bottom_frame, **btn_params, text="8", command=lambda: self.btn_click(8))
self.btn_8.configure(activebackground="black", bg='black')
self.btn_8.grid(row=1, column=6)
# nine
self.btn_9 = tk.Button(bottom_frame, **btn_params, text="9", command=lambda: self.btn_click(9))
self.btn_9.configure(activebackground="black", bg='black')
self.btn_9.grid(row=1, column=7)
# multiplication
self.btn_mult = tk.Button(bottom_frame, **btn_params, text="x", command=lambda: self.btn_click('*'))
self.btn_mult.grid(row=1, column=8)

# row 2
# sin function that returns value from -1 to 1 by default
self.btn_sin = tk.Button(
bottom_frame, **btn_params, text="sin", command=lambda: self.btn_click('fsin('))
self.btn_sin.grid(row=2, column=0)
# cos function that returns value from -1 to 1 by default
self.btn_cos = tk.Button(
bottom_frame, **btn_params, text="cos", command=lambda: self.btn_click('fcos('))
self.btn_cos.grid(row=2, column=1)
# tan function
self.btn_tan = tk.Button(bottom_frame, **btn_params, text="tan", command=lambda: self.btn_click('ftan('))
self.btn_tan.grid(row=2, column=2)
#
self.btn_log = tk.Button(bottom_frame, **btn_params, text="log", command=lambda: self.btn_click('log('))
self.btn_log.grid(row=2, column=3)
# outputs what is in self.recall
self.btn_MR = tk.Button(bottom_frame, **btn_params, text="MR", command=self.memory_recall)
self.btn_MR.grid(row=2, column=4)
# four
self.btn_4 = tk.Button(bottom_frame, **btn_params, text="4", command=lambda: self.btn_click(4))
self.btn_4.configure(activebackground="black", bg='black')
self.btn_4.grid(row=2, column=5)
# five
self.btn_5 = tk.Button(bottom_frame, **btn_params, text="5", command=lambda: self.btn_click(5))
self.btn_5.configure(activebackground="black", bg='black')
self.btn_5.grid(row=2, column=6)
# six
self.btn_6 = tk.Button(bottom_frame, **btn_params, text="6", command=lambda: self.btn_click(6))
self.btn_6.configure(activebackground="black", bg='black')
self.btn_6.grid(row=2, column=7)
# subtraction
self.btnSub = tk.Button(bottom_frame, **btn_params, text="-", command=lambda: self.btn_click('-'))
self.btnSub.grid(row=2, column=8)

# row 3
# sin inverse function
self.btn_sin_inverse = tk.Button(bottom_frame, **btn_params, text=u"sin-\u00B9", command=lambda: self.btn_click('arcsin('))
self.btn_sin_inverse.grid(row=3, column=0)
# cos inverse function
self.btn_cos_inverse = tk.Button(bottom_frame, **btn_params, text=u"cos-\u00B9", command=lambda: self.btn_click('arccos('))
self.btn_cos_inverse.grid(row=3, column=1)
# tan inverse function
self.btn_tan_inverse = tk.Button(bottom_frame, **btn_params, text=u"tan-\u00B9", command=lambda: self.btn_click('arctan('))
self.btn_tan_inverse.grid(row=3, column=2)
# takes the natural log
self.btn_ln = tk.Button(bottom_frame, **btn_params, text="ln", command=lambda: self.btn_click('log1p('))
self.btn_ln.grid(row=3, column=3)
# adds current self.expression to self.recall string
self.btn_M_plus = tk.Button(bottom_frame, **btn_params, text="M+", command=self.memory_add)
self.btn_M_plus.grid(row=3, column=4)
# one
self.btn_1 = tk.Button(bottom_frame, **btn_params, text="1", command=lambda: self.btn_click(1))
self.btn_1.configure(activebackground="black", bg='black')
self.btn_1.grid(row=3, column=5)
# two
self.btn_2 = tk.Button(bottom_frame, **btn_params, text="2", command=lambda: self.btn_click(2))
self.btn_2.configure(activebackground="black", bg='black')
self.btn_2.grid(row=3, column=6)
# three
self.btn_3 = tk.Button(bottom_frame, **btn_params, text="3", command=lambda: self.btn_click(3))
self.btn_3.configure(activebackground="black", bg='black')
self.btn_3.grid(row=3, column=7)
bottom_frame, **btn_params, text="+", command=lambda: self.btn_click('+'))

# row 4
# factorial function
self.btn_fact = tk.Button(bottom_frame, **btn_params, text="n!", command=lambda: self.btn_click('factorial('))
self.btn_fact.grid(row=4, column=0)
# square function
self.btn_sqr = tk.Button(bottom_frame, **btn_params, text=u"x\u00B2", command=lambda: self.btn_click('**2'))
self.btn_sqr.grid(row=4, column=1)
# to the power of function
self.btn_power = tk.Button(bottom_frame, **btn_params, text="x^y", command=lambda: self.btn_click('**'))
self.btn_power.grid(row=4, column=2)
# stores previous expression as an answer value
self.btn_ans = tk.Button(bottom_frame, **btn_params, text="ans", command=self.answer)
self.btn_ans.grid(row=4, column=3)
# comma to allow for more than one parameter!
self.btn_comma = tk.Button(bottom_frame, **btn_params, text=",", command=lambda: self.btn_click(','))
self.btn_comma.grid(row=4, column=4)
# zero
self.btn_0 = tk.Button(bottom_frame, **btn_params, text="0", command=lambda: self.btn_click(0))
self.btn_0.configure(activebackground="black", bg='black', width=7, bd=5)
self.btn_0.grid(row=4, column=5, columnspan=2)
# equals button
self.btn_eq = tk.Button(bottom_frame, **btn_params, text="=", command=self.btn_equal)
self.btn_eq.configure(bg='Gray', activebackground='#009999')
self.btn_eq.grid(row=4, column=7)
# decimal to convert to float
self.btn_dec = tk.Button(bottom_frame, **btn_params, text=".", command=lambda: self.btn_click('.'))
self.btn_dec.grid(row=4, column=8)```

We created a Calculator class with the following instance variables: ‘op’ (stores the current operator clicked by the user), ‘M’ (stores memory), ‘isTrue 2nd’ (stores True if ‘2nd’ is clicked and activates the second set of scientific functions like sin-1, 10x. ex, y x in place of sin, log, ln, xy), ‘is degree’ (True if ‘deg’ is on, takes radians for trigonometric operations when ‘deg’ is clicked to ‘rad’ and is degree = False) and ‘decimal clicked’ (turns True when user clicks ‘.’)

### Step.4: Create functions for the buttons in Calculator

```    # allows button you click to be put into self.expression

def btn_click(self, expression_val):
if len(self.expression) >= 23:
self.expression = self.expression
self.text_input.set(self.expression)
else:
self.expression = self.expression + str(expression_val)
self.text_input.set(self.expression)

# clears last item in string

def btn_clear1(self):
self.expression = self.expression[:-1]
self.text_input.set(self.expression)

# adds in a negative sign

def change_signs(self):
self.expression = self.expression + '-'
self.text_input.set(self.expression)

# clears memory_recall

def memory_clear(self):
self.recall = ""

# adds whatever is on the screen to self.recall

self.recall = self.recall + '+' + self.expression

# uses whatever is stored in memory_recall

self.text_input.set(self.expression)

# uses whatever is stored in memory_recall
def memory_recall(self):
if self.expression == "":
self.text_input.set('0' + self.expression + self.recall)
else:
self.text_input.set(self.expression + self.recall)

# changes self.convert_constant to a string that allows degree conversion when button is clicked
def convert_deg(self):
global convert_constant
global inverse_convert_constant
convert_constant = pi / 180
inverse_convert_constant = 180 / pi
self.btn_Deg["foreground"] = 'RED'

global convert_constant
global inverse_convert_constant
convert_constant = 1
inverse_convert_constant = 1
self.btn_Deg["foreground"] = 'white'

# clears self.expression

def btn_clear_all(self):
self.expression = ""
self.text_input.set("")

# converts self.expression into a mathematical expression and evaluates it

def btn_equal(self):
self.sum_up = str(eval(self.expression))
self.text_input.set(self.sum_up)
self.expression = self.sum_up```

### Step.5: Making Tkinter Layout

```# tkinter layout
root = tk.Tk()
b = Calculator(root)
root.title("Scientific Calculator!")
root.geometry("650x490+50+50")
root.resizable(False, False)
root.mainloop()```

In the end, it is time to start designing the program’s graphical user interface for our Scientific Calculator in Python using Tkinter. We will begin by launching Tkinter and creating a window for the Scientific calculator. In this case, we set the window size to 650×490+50+50, and the window resizability to false.

## Complete code for Scientific Calculator in Python using Tkinter

```import tkinter as tk
from math import *

# used to switch between units of rad, and deg
convert_constant = 1
inverse_convert_constant = 1

btn_params = {'padx': 16, 'pady': 1, 'bd': 4, 'fg': 'white', 'bg': 'black', 'font': ('arial', 18),
'width': 2, 'height': 2, 'relief': 'flat', 'activebackground': "black"}

#Functions for the buttons
def fsin(arg):
return sin(arg * convert_constant)

def fcos(arg):
return cos(arg * convert_constant)

def ftan(arg):
return tan(arg * convert_constant)

def arcsin(arg):
return inverse_convert_constant * (asin(arg))

def arccos(arg):
return inverse_convert_constant * (acos(arg))

def arctan(arg):
return inverse_convert_constant * (atan(arg))

# Here are the methods inside class for all the Buttons in the Scientific Calculator.
class Calculator:
def __init__(self, master):
# expression that will be displayed on screen
self.expression = ""
# be used to store data in memory
self.recall = ""
self.sum_up = ""
# create string for text input
self.text_input = tk.StringVar()
self.master = master
# set frame showing inputs and title
top_frame = tk.Frame(master, width=650, height=10,
bd=10, relief='flat', bg='gray')
top_frame.pack(side=tk.TOP)
# set frame showing all buttons
bottom_frame = tk.Frame(
master, width=650, height=470, bd=2, relief='flat', bg='black')
bottom_frame.pack(side=tk.BOTTOM)

# Here is the code for Display of Calculator.
# entry interface for inputs
txt_display = tk.Entry(top_frame, font=('arial', 36), relief='flat', bg='black', fg='white', textvariable=self.text_input, width=60, bd=12, justify='right')
txt_display.pack()

# row 0
# left bracket button
self.btn_left_brack = tk.Button(
bottom_frame, **btn_params, text="(", border=1, command=lambda: self.btn_click('('))
self.btn_left_brack.grid(row=0, column=0)
# right bracket button
self.btn_right_brack = tk.Button(
bottom_frame, **btn_params, text=")", command=lambda: self.btn_click(')'))
self.btn_right_brack.grid(row=0, column=1)
# takes e to some exponent that you insert into the function
self.btn_exp = tk.Button(
bottom_frame, **btn_params, text="exp", command=lambda: self.btn_click('exp('))
self.btn_exp.grid(row=0, column=2)
# constant pi
self.btn_pi = tk.Button(
bottom_frame, **btn_params, text="π", command=lambda: self.btn_click('pi'))
self.btn_pi.grid(row=0, column=3)
# square root
self.btn_sqrt = tk.Button(
bottom_frame, **btn_params, text="sqrt", command=lambda: self.btn_click('sqrt('))
self.btn_sqrt.grid(row=0, column=4)
# clears self.expression
self.btn_clear = tk.Button(
bottom_frame, **btn_params, text="C", command=self.btn_clear_all)
self.btn_clear.grid(row=0, column=5)
# deletes last string input
self.btn_del = tk.Button(
bottom_frame, **btn_params, text="AC", command=self.btn_clear1)
self.btn_del.grid(row=0, column=6)
# inputs a negative sign to the next entry
self.btn_change_sign = tk.Button(
bottom_frame, **btn_params, text="+/-", command=self.change_signs)
self.btn_change_sign.grid(row=0, column=7)
# division
self.btn_div = tk.Button(
bottom_frame, **btn_params, text="/", command=lambda: self.btn_click('/'))
self.btn_div.grid(row=0, column=8)

# row 1
# changes trig function outputs to degrees
self.btn_Deg = tk.Button(bottom_frame, **btn_params, activeforeground='gray', text="Deg", command=self.convert_deg)
self.btn_Deg.grid(row=1, column=0)
# changes trig function outputs to default back to radians
# cubes a value
self.cube = tk.Button(bottom_frame, **btn_params, text=u"x\u00B3", command=lambda: self.btn_click('**3'))
self.cube.grid(row=1, column=2)
# takes the absolute value of an expression
self.btn_abs = tk.Button(
bottom_frame, **btn_params, text="abs", command=lambda: self.btn_click('abs' + '('))
self.btn_abs.grid(row=1, column=3)
# 'memory clear' button. Wipes self.recall to an empty string
self.btn_MC = tk.Button(
bottom_frame, **btn_params, text="MC", command=self.memory_clear)
self.btn_MC.grid(row=1, column=4)
# seven
self.btn_7 = tk.Button(bottom_frame, **btn_params, text="7", command=lambda: self.btn_click(7))
self.btn_7.configure(activebackground="black", bg='black')
self.btn_7.grid(row=1, column=5)
# eight
self.btn_8 = tk.Button(bottom_frame, **btn_params, text="8", command=lambda: self.btn_click(8))
self.btn_8.configure(activebackground="black", bg='black')
self.btn_8.grid(row=1, column=6)
# nine
self.btn_9 = tk.Button(bottom_frame, **btn_params, text="9", command=lambda: self.btn_click(9))
self.btn_9.configure(activebackground="black", bg='black')
self.btn_9.grid(row=1, column=7)
# multiplication
self.btn_mult = tk.Button(bottom_frame, **btn_params, text="x", command=lambda: self.btn_click('*'))
self.btn_mult.grid(row=1, column=8)

# row 2
# sin function that returns value from -1 to 1 by default
self.btn_sin = tk.Button(
bottom_frame, **btn_params, text="sin", command=lambda: self.btn_click('fsin('))
self.btn_sin.grid(row=2, column=0)
# cos function that returns value from -1 to 1 by default
self.btn_cos = tk.Button(
bottom_frame, **btn_params, text="cos", command=lambda: self.btn_click('fcos('))
self.btn_cos.grid(row=2, column=1)
# tan function
self.btn_tan = tk.Button(bottom_frame, **btn_params, text="tan", command=lambda: self.btn_click('ftan('))
self.btn_tan.grid(row=2, column=2)
#
self.btn_log = tk.Button(bottom_frame, **btn_params, text="log", command=lambda: self.btn_click('log('))
self.btn_log.grid(row=2, column=3)
# outputs what is in self.recall
self.btn_MR = tk.Button(bottom_frame, **btn_params, text="MR", command=self.memory_recall)
self.btn_MR.grid(row=2, column=4)
# four
self.btn_4 = tk.Button(bottom_frame, **btn_params, text="4", command=lambda: self.btn_click(4))
self.btn_4.configure(activebackground="black", bg='black')
self.btn_4.grid(row=2, column=5)
# five
self.btn_5 = tk.Button(bottom_frame, **btn_params, text="5", command=lambda: self.btn_click(5))
self.btn_5.configure(activebackground="black", bg='black')
self.btn_5.grid(row=2, column=6)
# six
self.btn_6 = tk.Button(bottom_frame, **btn_params, text="6", command=lambda: self.btn_click(6))
self.btn_6.configure(activebackground="black", bg='black')
self.btn_6.grid(row=2, column=7)
# subtraction
self.btnSub = tk.Button(bottom_frame, **btn_params, text="-", command=lambda: self.btn_click('-'))
self.btnSub.grid(row=2, column=8)

# row 3
# sin inverse function
self.btn_sin_inverse = tk.Button(bottom_frame, **btn_params, text=u"sin-\u00B9", command=lambda: self.btn_click('arcsin('))
self.btn_sin_inverse.grid(row=3, column=0)
# cos inverse function
self.btn_cos_inverse = tk.Button(bottom_frame, **btn_params, text=u"cos-\u00B9", command=lambda: self.btn_click('arccos('))
self.btn_cos_inverse.grid(row=3, column=1)
# tan inverse function
self.btn_tan_inverse = tk.Button(bottom_frame, **btn_params, text=u"tan-\u00B9", command=lambda: self.btn_click('arctan('))
self.btn_tan_inverse.grid(row=3, column=2)
# takes the natural log
self.btn_ln = tk.Button(bottom_frame, **btn_params, text="ln", command=lambda: self.btn_click('log1p('))
self.btn_ln.grid(row=3, column=3)
# adds current self.expression to self.recall string
self.btn_M_plus = tk.Button(bottom_frame, **btn_params, text="M+", command=self.memory_add)
self.btn_M_plus.grid(row=3, column=4)
# one
self.btn_1 = tk.Button(bottom_frame, **btn_params, text="1", command=lambda: self.btn_click(1))
self.btn_1.configure(activebackground="black", bg='black')
self.btn_1.grid(row=3, column=5)
# two
self.btn_2 = tk.Button(bottom_frame, **btn_params, text="2", command=lambda: self.btn_click(2))
self.btn_2.configure(activebackground="black", bg='black')
self.btn_2.grid(row=3, column=6)
# three
self.btn_3 = tk.Button(bottom_frame, **btn_params, text="3", command=lambda: self.btn_click(3))
self.btn_3.configure(activebackground="black", bg='black')
self.btn_3.grid(row=3, column=7)
bottom_frame, **btn_params, text="+", command=lambda: self.btn_click('+'))

# row 4
# factorial function
self.btn_fact = tk.Button(bottom_frame, **btn_params, text="n!", command=lambda: self.btn_click('factorial('))
self.btn_fact.grid(row=4, column=0)
# square function
self.btn_sqr = tk.Button(bottom_frame, **btn_params, text=u"x\u00B2", command=lambda: self.btn_click('**2'))
self.btn_sqr.grid(row=4, column=1)
# to the power of function
self.btn_power = tk.Button(bottom_frame, **btn_params, text="x^y", command=lambda: self.btn_click('**'))
self.btn_power.grid(row=4, column=2)
# stores previous expression as an answer value
self.btn_ans = tk.Button(bottom_frame, **btn_params, text="ans", command=self.answer)
self.btn_ans.grid(row=4, column=3)
# comma to allow for more than one parameter!
self.btn_comma = tk.Button(bottom_frame, **btn_params, text=",", command=lambda: self.btn_click(','))
self.btn_comma.grid(row=4, column=4)
# zero
self.btn_0 = tk.Button(bottom_frame, **btn_params, text="0", command=lambda: self.btn_click(0))
self.btn_0.configure(activebackground="black", bg='black', width=7, bd=5)
self.btn_0.grid(row=4, column=5, columnspan=2)
# equals button
self.btn_eq = tk.Button(bottom_frame, **btn_params, text="=", command=self.btn_equal)
self.btn_eq.configure(bg='Gray', activebackground='#009999')
self.btn_eq.grid(row=4, column=7)
# decimal to convert to float
self.btn_dec = tk.Button(bottom_frame, **btn_params, text=".", command=lambda: self.btn_click('.'))
self.btn_dec.grid(row=4, column=8)

# functions
# allows button you click to be put into self.expression

def btn_click(self, expression_val):
if len(self.expression) >= 23:
self.expression = self.expression
self.text_input.set(self.expression)
else:
self.expression = self.expression + str(expression_val)
self.text_input.set(self.expression)

# clears last item in string

def btn_clear1(self):
self.expression = self.expression[:-1]
self.text_input.set(self.expression)

# adds in a negative sign

def change_signs(self):
self.expression = self.expression + '-'
self.text_input.set(self.expression)

# clears memory_recall

def memory_clear(self):
self.recall = ""

# adds whatever is on the screen to self.recall

self.recall = self.recall + '+' + self.expression

# uses whatever is stored in memory_recall

self.text_input.set(self.expression)

# uses whatever is stored in memory_recall

def memory_recall(self):
if self.expression == "":
self.text_input.set('0' + self.expression + self.recall)
else:
self.text_input.set(self.expression + self.recall)

# changes self.convert_constant to a string that allows degree conversion when button is clicked

def convert_deg(self):
global convert_constant
global inverse_convert_constant
convert_constant = pi / 180
inverse_convert_constant = 180 / pi
self.btn_Deg["foreground"] = 'RED'

global convert_constant
global inverse_convert_constant
convert_constant = 1
inverse_convert_constant = 1
self.btn_Deg["foreground"] = 'white'

# clears self.expression

def btn_clear_all(self):
self.expression = ""
self.text_input.set("")

# converts self.expression into a mathematical expression and evaluates it

def btn_equal(self):
self.sum_up = str(eval(self.expression))
self.text_input.set(self.sum_up)
self.expression = self.sum_up

# tkinter layout
root = tk.Tk()
b = Calculator(root)
root.title("Scientific Calculator!")
root.geometry("650x490+50+50")
root.resizable(False, False)
root.mainloop()```

## Conclusion

In this article, we built a Scientific Calculator in Python using Tkinter and defined what happens when a user interacts with a UI element. Using Frame widgets to create containers/windows in which to arrange UI components. Positioning Button widgets within a Frame widget using Tkinter’s Layout Manager. The grid layout manager was chosen for the Calculator application due to its precision compared to alternative layout techniques.