^

Difference between two numbers, subtraction, and "how many more" addition

The difference between two numbers is their distance; how far apart they are from each other on a number line. We look at this concept, and how it ties in with subtraction and addition. This lesson is meant for 2nd or 3rd grade.

(Note: the video uses the terminology "difference of" instead of "difference between". It means the same thing.)

We can always SUBTRACT the two numbers to find their difference. For example, to find the difference of 100 and 3, subtract 100 − 3. The difference is 97.

We can also use this idea to solve subtractions, especially those where the two numbers are fairly close to each other. What is 98 − 95? Think how far apart 98 and 95 are from each other. Just three steps. So, 98 − 95 = 3.

Lastly, the difference between two numbers can also be solved by thinking of "how many more" type of an addition. For example, to find the difference between 7 and 12, think: 7 + ____ = 12, or 7 and how many more makes 12? This ties in with the number line: if you are at 7, how many steps do you need to take to get to 12?


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



See also

Number rainbow & fact families with 11

Number rainbow & fact families with 12

Math Mammoth Grade 2 curriculum

Back to 2nd grade videos index

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. smile 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). smile

Peek at the previous tips here.

You will also receive:

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