^

# Estimating in multiplication: round the factors! (4th grade math)

An easy lesson where we estimate products using rounding. The basic rule is to round in such a manner that makes it easy for YOU to multiply mentally. In other words, there are no "hard and fast" rules as to HOW exactly you round when estimating, because it depends on your mental math capabilities.

One good principle to keep in mind is that it is helpful to round one factor UP, the other DOWN, in order to reduce or minimize the error of estimation.

In one example, I do two estimations and take the AVERAGE of those as the final estimation. So that is one more strategy you can use.

We also solve two word problems using estimation (instead of using long division, which could end up being more cumbersome).

This is meant for 4th grade math and on up, as many math curricula never teach strategies for rounding and estimating, or how estimation can be used to solve word problems.

If you cannot see the video above, click here for an alternative video player.

Estimating the final result (in subtraction and in a word problem)

Math Mammoth Grade 4 curriculum

Back to the list of 4th grade videos

Back to the index of all videos

WAIT!

Receive my monthly collection of math tips & resources directly in your inbox — and get a FREE Math Mammoth book!

We respect your email privacy.
You can unsubscribe at any time.

### Math Mammoth Tour

Confused about the different options? Take a virtual email tour around Math Mammoth! You'll receive:

An initial email to download your GIFT of over 400 free worksheets and sample pages from my books. Six other "TOURSTOP" emails that explain the important things and commonly asked questions concerning Math Mammoth curriculum. (Find out the differences between all these different-colored series!)

This way, you'll have time to digest the information over one or two weeks, plus an opportunity to ask me personally about the curriculum.
A monthly collection of math teaching tips & Math Mammoth updates (unsubscribe any time)
We respect your email privacy.

Note: You will FIRST get an email that asks you to confirm your email address. If you cannot find this confirmation email, please check your SPAM/JUNK folder.

### "Mini" Math Teaching Course

This is a little "virtual" 2-week course, where you will receive emails on important topics on teaching math, including:

- How to help a student who is behind
- Troubles with word problems
- Teaching multiplication tables
- Why fractions are so difficult
- The value of mistakes
- Should you use timed tests
- And more!

You will also receive:

A GIFT of over 400 free worksheets and sample pages from my books right in the very beginning. A monthly collection of math teaching tips & Math Mammoth updates (unsubscribe any time)
We respect your email privacy.

Note: You will FIRST get an email that asks you to confirm your email address. If you cannot find this confirmation email, please check your SPAM/JUNK folder.

### Maria's Math Tips

Enter your email to receive math teaching tips, resources, Math Mammoth news & sales, humor, and more! I tend to send out these tips about once monthly, near the beginning of the month, but occasionally you may hear from me twice per month (and sometimes less often).

You will also receive:

• A GIFT of over 400 free worksheets and sample pages from my books.
We respect your email privacy.