MENTAL ARITHMETIC: ADDITION PROBLEMS To see the answer, pass your mouse over the colored area. 1. Add each column mentally. Regroup to compose a multiple of 10.
2. Adding by endings. Add the following from left to right. Then 2. a) 9 + 3 + 5 + 6 + 8 + 7 + 9 = 47 2. b) 8 + 8 + 7 + 4 + 5 + 9 + 6 + 7 = 54 2. c) 9 + 4 + 8 + 2 + 6 + 8 + 3 + 7 + 7 + 9 = 63 2. d) 3 + 8 + 7 + 5 + 5 + 6 + 8 + 2 + 9 + 6 = 59 3. Add each column mentally. Add the tens, then add the ones. 3. 10 + 35 = 45 50 + 34 = 84 30 + 75 = 105 64 + 70 = 134 3. 20 + 41 = 61 30 + 45 = 75 90 + 58 = 148 85 + 40 = 125 3. 30 + 27 = 57 70 + 16 = 86 80 + 64 = 144 92 + 20 = 112 3. 40 + 18 = 58 50 + 28 = 78 70 + 88 = 158 78 + 50 = 128 3. 30 + 67 = 97 40 + 57 = 97 60 + 92 = 152 31 + 80 = 111 4. Add each column mentally. 150 + 30 = 180 160 + 61 = 221 240 + 50 = 290 240 + 72 = 312 310 + 43 = 353 380 + 84 = 464 420 + 55 = 475 460 + 91 = 551 530 + 45 = 575 550 + 79 = 629 660 + 39 = 699 690 + 45 = 735 780 + 42 = 822 870 + 86 = 956 Add each column mentally. Add the tens, then add the ones.
Add the hundreds, then the tens, then the ones.
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