D5 - Practice Makes Perfect

1. Write a program that accepts a number, and print to the console if its negative, positive or 0.

2. Write a program that reads a number and return it's opposite. If 5 returns -5. If -12 returns 12 etc. Do it without using the native Math object, only with if statements (or even without).

3. Write a program that accepts 5 inputs as numbers. Calculate the sum and the average of them.

4. Write a program that accepts 3 numbers and prints the biggest of them.

5. Store a year in a variable and check if this year is a leap year (366 days) given that leap years  are 2016, 2012, 2008, 2004, 2000 etc. Print to the console 'yes' or 'no' accordingly.