Junior 7

1. Write a program to convert a hexadecimal number to decimal number.

Hexadecimal number: FF
Decimal number: 255

2. Write a program to convert a decimal number to hexadecimal number. 

Decimal number: 255
Hexadecimal number: FF

3. Write a program to check if two given non-negative integers have the same last digit.

23, 25
567, 237

4. Write a program to calculate the factorial of a given number.

Input the number : 4
The Factorial of 4 is: 24