This exercise is the next in the series of multiples...meaning after Multiples Challenge 1. The practice sheet is designed for 5 minutes (challenging), but students can do it with daily practice and, the added skill set to their repertoire is exceedingly beneficial. If a student can count by 20's, for example, then that student can count by 200's or 2,000's with relative ease. Note: Knowing the number "15" are extremely valuable for elapsed time and analog/digital clock work. The number "25" are useful with money. However, all numbers given on the sheet are repetitive numbers that arise in daily problem solving exercises.