Rounding to the Nearest Ten: Grandma Bea's Cookie Boxes

In Millie’s Kitchen, Grandma Bea packs cookies in boxes of 10. When Millie wants to know about how many cookies there are, she rounds to the nearest ten: which full number of boxes is it closest to?

Remember: Look at the ones digit. 0, 1, 2, 3 or 4: round down (34 rounds to 30). 5 or more rounds up (35 rounds to 40, and 37 rounds to 40).

Magic trick: Picture a hill: 0 to 4 haven’t reached the top, so they roll back down to the ten before. 5 to 9 have reached the top and roll forward to the next ten.