Increase aptitude and accuracy in adding numbers with results not exceeding 100, with more than 50 sets of exercises, along with exercise answers. The exercises are arranged in order of difficulty as follows: Blue zone: Adding single digit numbers between 0-9 and having a result not exceeding 10. Green zone: Adding numbers with a result. The number is not more than 20. Yellow zone: adding numbers with results between 20-50. Pink zone: adding numbers with results between 50-100. Red zone: Key