Step 1: See if the first number after the decimal point is greater than 4.
Step 2: If the number is greater than 4, drop the decimal part and add 1 to your number. Otherwise just drop the decimal part.
Example 1: Round 35.56
The first number after the decimal point is 5. This is greater than 4 so our rounded number is 35 + 1 = 36.
Example 2: Round 1.3333
The first number after the decimal point is 3. This is not greater than 4 so our rounded number is 1.