Question

erika wants to give 5 stickers to everyone in her class her class sits in 4 rows of 7 and erika says shell need 140 stickers

Answer 1

4x7=28 students
28x5=140 stickers

Answer 2

This is correct because There are 4 rows of 7 meaning there in 28 students(7 times 4). If you take 140 divided by 5 (this meaning that you're seeing if 140 stickers will be enough for the class) you get 28. So 28 students will each get 5 stickers.