Okay, phrens, you're teaching your students how to round numbers and this is what you are NOT going to do:
"Students, today we're going to learn how round numbers to the nearest hundreds. To round a number to the hundreds, start by placing your finger on the number furthest to the left (places finger on number) and then look over to the right and then sing this song, "If it's less than 4 or smaller, round it down; if it's 5 or greater, then go right up!" (If you'll pardon the pun.) Then give your students a sheet of 30 of these problems and have them do it individually in complete silence....
First of all, this activity explains the RIGHT way to teach rounding using deductive reasoning, instead of "teachersplaining." it's a nice little lesson that takes about 20 - 30 minutes and it gets your kids thinking, instead of blindly following your directions.
Then there's the actual activity: Ten different number mystery booklets where your students work backwards: that is, instead of rounding off some random number that you've pulled out of your tuchus, they are given the rounded number and have to figure out what the non-rounded number could be.... they do this when the number is rounded to the nearest hundred and then the nearest ten. The final clue reviews some mathematical terminology, including place value, digit sum and palindrome.
Includes answer sheets, answer key, Do It Yourself sheet and so much more!