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Unit 3
Adding and Subtracting
Whole Numbers
1. Addition
4
+...1
5
34
+12
46
333
+ 666
999
Adding numbers with
different places requires
lining up the units column.
21 +4+234
Carrying
10's
100's
1
17
+~
25
1
111
+ 97
208
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21
+ 4
234
259
1,000's
Sums larger than 9 require carrying one
or more tens one place to the left. Sums
larger than 99 require carrying one or
more hundreds one place to the left, etc.
1
2,767
+ 5.831
8,598
2. Subtraction
5
-...1
4
36
---2
34
99
- 66
33
299
- 88
211
5
-1 ~
4
4+ 1= 5
Check your answer by
seeing if the answer
plus the middle number
equals the top number.
Borrowing
A.
B.
C.
Subtracting a larger number such as 8, from a smaller number
such as 4, requires borrowing a ten from the place to the left.
The place of the number being borrowed from determines the
amount being borrowed.
The number being borrowed from must be lowered by one.
10's
100's
5 14
4 10
~~
- 38
26
$.9'8
-1 55
353
1,OOO's
7 16
j8' , J1'3 3
-5.821
2,81
2
12
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