Subtraction Shortcuts and Tips

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					Subtraction Shortcuts
      and Tips

  By Monica Yuskaitis
Subtracting Across Zeros


      302
      198
Step 1 – Borrow 1 from the 30


         302
         198
Step 2 – Cross out the 30


      302
      198
Step 3 – Write a 29 above the 30
            2 9

          302
          198
Step 4 – Write a 1 in front of the 2
            2 9

           3 0 12
           198
Step 5 – Subtract 8 from 12
         2 9

       3 0 12
       198
            4
Step 6 – Subtract 9 from 9
         2 9

      3 0 12
      198
        04
Step 7 – Subtract 1 from 2
         2 9

      3 0 12
      198
      104
We’re Finished
  2 9

 3 0 12
 198
 104
Second Example


8002
3765
Step 1 – Borrow 1 from 800


     8002
     3765
Step 2 – Cross out the 800


    8002
    3765
Step 3 – Write 799 above the 800
         7 9 9
        8002
        3765
Step 4 – Write a 1 next to the 2
         7 9 9
       8 0 0 12
       3765
Step 5 – Subtract 5 from the 12
        7 9 9
       8 0 0 12
       3765
              7
Step 6 – Subtract 6 from the 9
       7 9 9
      8 0 0 12
      3765
          37
Step 7 – Subtract 6 from the 9
       7 9 9
      8 0 0 12
      3765
        2 37
Step 7 – Subtract 3 from the 7
       7 9 9
      8 0 0 12
      3765
      4 2 37
We’re Finished
7 9 9
8 0 0 12
3765
4 2 37
It’s Your Turn
6 9 9
7 0 0 15
2836
4 1 69
It’s Your Turn Again
   8 9 9
  9 0 0 14
  7956
  1 0 48
Subtraction Tips
  Never subtract the top number
    from the bottom number
           613
           279
           466
Your answer will always be wrong.
 Never borrow unless you need to
               5
           9 6 12
           841
Your answer will always be wrong.
 Practice your subtraction facts
18 –9= 9       18 – 5 = 13
18 – 7 = 11    18 – 3 = 15
16 – 8 = 8     16 – 7 =  9
14 – 8 = 6     14 – 6 =  8
12 – 9 = 3     12 – 4 = 8
11 – 3 = 8     11 – 7 = 4
15 – 7 = 8     15 – 6 = 9
9 – 3 =  6     9 – 5 =   4

				
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