From: Kim Davis
To: Teacher2Teacher Public Discussion
When teaching my fourth graders rounding, I have a picture on my wall of a skinny stick man with 0,1,2,3,4 beside him and a round stick man with 5,6,7,8,9 next to him (you could replace the skinny guy with a short guy and the round guy with a tall guy if weight is an issue). Now, when we are rounding 453 to the nearest tens, we underline the tens guy (we always underline the guy who's going to do the eating). The guy you're rounding to always eats his neighbor to the right. If his neighbor is a 0,1,2,3, or 4 he doesn't gain weight or grow. If it's a 5,6,7,8,or 9, the eater grows. The number to the right is gone because the "eater" ate him and now there's a zero there. He NEVER bothers his neighbor to the left. If it is a large number, like 4,625 and we're rounding to say, the thousands, the 4 eats the 6, the eater grows into a 5, he ate the guy on his right so there's a zero there and the other two numbers ran away to keep from being eaten! There are zeros in their places too! My students never forget this! I've learned to do it in Spanish too! Key questions: 1. Who's going to do the eating? Underline him. 2. Does he grow or stay the same? 3. Replace all the right neighbor(s)with zeros (one got eaten and the rest ran away). 4. We never eat the left neighbors.
Math Forum Home || The Math Library || Quick Reference || Math Forum Search