MENTAL ARITHMETIC:  ADDITION

PROBLEMS 2

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11.  Rounding off.  Add mentally.

11.  a)  98 + 98 + 98 = 294                 b)  2.95 + 6.95 + 8.95  = 18.85

11.  c)  4.99 + 7.99 + 1.99 = 14.97         d)  2.75 + .95 = 3.70

12.  Regroup to form a multiple of 10.

49 + 25 = 50 + 24 = 74   44 + 57 = 101
 
18 + 36 = 20 + 34 = 54   69 + 74 = 143
 
 
67 + 24 = 91   85 + 56 = 141
 
31 + 78 = 109   92 + 39 = 131
 
 
55 + 37 = 92   86 + 75  = 161

13.  Add these dollars and cents mentally.  Add the cents first.

3.59 + 5.25 = 8.84          5.75 + 2.36 = 8.11

2.48 + 4.45 = 6.93         7.57 + 4.84 = 12.41

5.29 + 1.23 = 6.52         8.39 + 5.86 = 14.25

4.77 + 9.93 = 14.70         9.56 + 5.78 = 15.34

14.  If one item costs $3.59, and another, $4.79, what do you pay?  8.38

15.  If you buy two tubes of toothpaste at $2.29 each, what do you pay?
16.  4.58

16.  Regrouping.  Add mentally.

16.  a)  17 + 56 + 3 = 20 + 56 = 76

16.  b)  4 + 5 + 4 + 5 + 4 + 5 = 27

16.  c)  10 + 6 + 10 + 6 + 10 + 6  = 48

16.  c)  How much is 3 × 16? = 48

16.  d)  2 + 9 + 8 + 1 + 3 + 5 + 7  = 35


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