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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Saturday March 07 2026
12:55:20 AM | Saturday March 07 2026
12:55:20 AMFlip Answers |
| 1) | 392 * 408 = | | 1) 400 * 400 - 8 * 8 = 159936 |
| 2) | 398 * 402 = | | 2) 400 * 400 - 2 * 2 = 159996 |
| 3) | 110 * 90 = | | 3) 100 * 100 - 10 * 10 = 9900 |
| 4) | 310 * 290 = | | 4) 300 * 300 - 10 * 10 = 89900 |
| 5) | 407 * 393 = | | 5) 400 * 400 - 7 * 7 = 159951 |
| 6) | 102 * 98 = | | 6) 100 * 100 - 2 * 2 = 9996 |
| 7) | 393 * 407 = | | 7) 400 * 400 - 7 * 7 = 159951 |
| 8) | 402 * 398 = | | 8) 400 * 400 - 2 * 2 = 159996 |
| 9) | 105 * 95 = | | 9) 100 * 100 - 5 * 5 = 9975 |
| 10) | 303 * 297 = | | 10) 300 * 300 - 3 * 3 = 89991 |
| 11) | 36 * 143 - 36 * 43 = | | 11) ( 143 - 43) * 36 = 3600 |
| 12) | 79 * 174 - 74 * 79 = | | 12) ( 174 - 74) * 79 = 7900 |
| 13) | 83 * 161 + 83 * 39 = | | 13) ( 161 + 39) * 83 = 16600 |
| 14) | 56 * 82 + 44 * 82 = | | 14) ( 44 + 56) * 82 = 8200 |
| 15) | 30 * 256 - 30 * 56 = | | 15) ( 256 - 56) * 30 = 6000 |
| 16) | 89 * 60 + 40 * 89 = | | 16) ( 40 + 60) * 89 = 8900 |
| 17) | 270 * 69 - 69 * 70 = | | 17) ( 270 - 70) * 69 = 13800 |
| 18) | 33 * 42 + 58 * 33 = | | 18) ( 58 + 42) * 33 = 3300 |
| 19) | 145 * 57 + 55 * 57 = | | 19) ( 145 + 55) * 57 = 11400 |
| 20) | 82 * 134 + 66 * 82 = | | 20) ( 134 + 66) * 82 = 16400 |
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Score: ______________ | |
