Download presentation

Presentation is loading. Please wait.

Published byJohnathan Curtis Modified over 8 years ago

2
The Partial-Sums Algorithm Used for adding multi-digit numbers. Used for adding multi-digit numbers. Created by Paula Cantera Elk Neck Elementary

3
Children should be encouraged to check their answers to see whether they make sense. Whether done in advance or as a final check, it is desirable to make a “ballpark estimate” of the answer.

4
One way to make a “ballpark estimate” is to round each addend to the nearest ten or hundred, depending on the numbers being added.

5
For example: 63 + 24 is close to 60 + 20. Students can easily add 60 + 20 to get 80. Any answer not close to 80 would not be a reasonable answer and should be checked for accuracy.

6
When using the partial-sums algorithm, the partial sums may be calculated in any order - it does not matter whether you add the tens first or the ones first.

7
Think of each addend in its expanded form: 63 24 60 + 3 20 + 4 +

8
Now add the tens 80 63 24 60+3 20+4 60+ 20

9
Next add the ones 80 63 24 60+3 20+4 60+ 20 3+ 4 7 + +

10
Finally, add the partial sums. 80 63 24 60+3 20+4 60+ 20 3+ 4 7 + + 87

11
Of course this can be expanded to work with 3-digit numbers, and 4-digit…….

12
342 145+ 300 + 40 + 2 100 + 40 + 5 400 80 7 + 487

13
Partial-Sums Algorithm Just one way to add multi-digit numbers. Try some at home today! Just one way to add multi-digit numbers. Try some at home today!

Similar presentations

© 2023 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google