Math Main Page => Exercises - Math III
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Goal: to practice how to make use of distributive property on special numbers, like (A + B) * (A - B) = A*A - B*B, A*C +B*C = (A + B ) *C, A*C - B*C = (A-B) * C
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Wednesday January 21 2026
08:08:24 AM | Wednesday January 21 2026
08:08:24 AMFlip Answers |
| 1) | 405 * 395 = | | 1) 400 * 400 - 5 * 5 = 159975 |
| 2) | 191 * 209 = | | 2) 200 * 200 - 9 * 9 = 39919 |
| 3) | 197 * 203 = | | 3) 200 * 200 - 3 * 3 = 39991 |
| 4) | 98 * 102 = | | 4) 100 * 100 - 2 * 2 = 9996 |
| 5) | 203 * 197 = | | 5) 200 * 200 - 3 * 3 = 39991 |
| 6) | 90 * 110 = | | 6) 100 * 100 - 10 * 10 = 9900 |
| 7) | 105 * 95 = | | 7) 100 * 100 - 5 * 5 = 9975 |
| 8) | 408 * 392 = | | 8) 400 * 400 - 8 * 8 = 159936 |
| 9) | 194 * 206 = | | 9) 200 * 200 - 6 * 6 = 39964 |
| 10) | 295 * 305 = | | 10) 300 * 300 - 5 * 5 = 89975 |
| 11) | 135 * 70 + 70 * 65 = | | 11) ( 135 + 65) * 70 = 14000 |
| 12) | 34 * 134 + 66 * 34 = | | 12) ( 134 + 66) * 34 = 6800 |
| 13) | 60 * 62 + 38 * 60 = | | 13) ( 38 + 62) * 60 = 6000 |
| 14) | 154 * 67 - 67 * 54 = | | 14) ( 154 - 54) * 67 = 6700 |
| 15) | 166 * 83 - 66 * 83 = | | 15) ( 166 - 66) * 83 = 8300 |
| 16) | 38 * 78 + 78 * 62 = | | 16) ( 62 + 38) * 78 = 7800 |
| 17) | 40 * 26 + 26 * 160 = | | 17) ( 160 + 40) * 26 = 5200 |
| 18) | 142 * 92 - 92 * 42 = | | 18) ( 142 - 42) * 92 = 9200 |
| 19) | 50 * 71 + 29 * 50 = | | 19) ( 29 + 71) * 50 = 5000 |
| 20) | 56 * 29 + 71 * 56 = | | 20) ( 29 + 71) * 56 = 5600 |
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Score: ______________ | |
