Hey fellow 5th grade teachers, I am just wondering how you approach estimations. In all the years I have taught this is one of the more difficult concepts for 5th graders to learn.

I also teach 5th grade math. We always have a lesson on compatible numbers "Happy" numbers. I tell them if they know their multiplication facts, they've got it made!! I have always struggled with estimation until this year with our new series. For multiplication, rounding is estimating but for division it is more about compatible numbers.

When teaching multiplication 87 x 403. Round the smallest number first....87 to 90. Then 403 to 400. Multiply 9 x 4 = 36, so 90 x 400 = 36 plus 3 zeros or 36,000. The main goal is to round to the largest place value so that you are working with powers of 10!!

I want students to use estimation in real-life so we discuss why people estimate quantities and reasonable answers for computation. For multiplication, addition, and subtraction I use rounding and front-end estimation as strategies. I try to get students to use compatible numbers for division. This is very helpful when dividing by 2-digit divisors.

Thanks for the responses. I do teach them compatible numbers, but for some odd reason there's a good portion of kiddos who think that rounding is synonymous with estimation or just look at me like as if estimation is never used in real life (ha!). I do like trying to attach estimation to powers of 10 numbers though, maybe I'll try that.

This concept is always hard on my fifth graders. In my opinion, they have to master it on their own time schedule. As I continue to model with the stragglers, they slowly get the hang of it. Many opportunities are given that go past the initial lesson. (Five minutes here or there as a quick review or math commercial break.) Also, an anchor chart for referencing is hung on the wall and a model is created in their math journal.

When students just have to estimate to see if their answer is reasonable, one thing I emphasize as that although sometimes there is a "right and a wrong" answer, other times there is not and they may get a different answer than their friends depending on how they rounded. I talk about how it's the reasoning that counts and that both answers could be right, the important piece is that however you rounded or estimated, you did it correctly and can explain it, not that your answer matches a classmate's answer exactly.

Have you tried the site estimation180.com ? It is a fabulous site! They have a picture for every day of the year that uses estimation! The kids have to make an estimate. Answers are submitted through a Google form. It's a great way to build number sense. Students have to make the estimate, explain how they did it, and also come up with an estimate that is NOT realistic. My kids last year BEGGED to use this. I haven't had them use it yet this year.

I just went to a training where they showed up one, and then the following several days built on that same original estimation. Looks really well organized!