the partial-sums algorithm used for adding multi-digit numbers. used for adding multi-digit numbers....
TRANSCRIPT
The Partial-SumsAlgorithm
The Partial-SumsAlgorithm
Used for adding multi-digit numbers.
Used for adding multi-digit numbers.
Created by Paula Cantera Elk Neck Elementary
Children should be encouraged to check their answers to see whether they make sense.
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.
Whether done in advance or as a final check, it is desirable to make a “ballpark estimate” of the answer.
One way to make a “ballpark estimate” is to round each addend to the nearest ten or hundred, depending on thenumbers being added.
One way to make a “ballpark estimate” is to round each addend to the nearest ten or hundred, depending on thenumbers being added.
For example:For example:
63 + 24 is close to 60 + 20.63 + 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.
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.
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.
Think of each addend in its expanded form:Think of each addend in its expanded form:
6324
60 + 320 + 4+
Now add the tensNow add the tens
80
6324
60 + 320 + 4
60 + 20
Next add the onesNext add the ones
80
6324
60 + 320 + 4
60 + 203 + 4
7
+
+
Finally, add the partial sums.Finally, add the partial sums.
80
6324
60 + 320 + 4
60 + 203 + 4
7
+
+87
Of course this can be expanded to work with 3-digit numbers, and 4-digit…….
Of course this can be expanded to work with 3-digit numbers, and 4-digit…….
342145+
300 + 40 + 2100 + 40 + 5400
807+
487
Partial-Sums Algorithm Partial-Sums AlgorithmJust 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!