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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Monday April 20 2026
01:11:41 AM | Monday April 20 2026
01:11:41 AMFlip Answers |
| 1) | 191 * 209 = | | 1) 200 * 200 - 9 * 9 = 39919 |
| 2) | 201 * 199 = | | 2) 200 * 200 - 1 * 1 = 39999 |
| 3) | 305 * 295 = | | 3) 300 * 300 - 5 * 5 = 89975 |
| 4) | 403 * 397 = | | 4) 400 * 400 - 3 * 3 = 159991 |
| 5) | 410 * 390 = | | 5) 400 * 400 - 10 * 10 = 159900 |
| 6) | 198 * 202 = | | 6) 200 * 200 - 2 * 2 = 39996 |
| 7) | 94 * 106 = | | 7) 100 * 100 - 6 * 6 = 9964 |
| 8) | 407 * 393 = | | 8) 400 * 400 - 7 * 7 = 159951 |
| 9) | 99 * 101 = | | 9) 100 * 100 - 1 * 1 = 9999 |
| 10) | 307 * 293 = | | 10) 300 * 300 - 7 * 7 = 89951 |
| 11) | 62 * 27 + 27 * 38 = | | 11) ( 38 + 62) * 27 = 2700 |
| 12) | 87 * 257 - 87 * 57 = | | 12) ( 257 - 57) * 87 = 17400 |
| 13) | 60 * 247 - 47 * 60 = | | 13) ( 247 - 47) * 60 = 12000 |
| 14) | 52 * 51 + 48 * 51 = | | 14) ( 52 + 48) * 51 = 5100 |
| 15) | 160 * 89 + 89 * 40 = | | 15) ( 160 + 40) * 89 = 17800 |
| 16) | 65 * 155 - 65 * 55 = | | 16) ( 155 - 55) * 65 = 6500 |
| 17) | 37 * 85 + 85 * 63 = | | 17) ( 37 + 63) * 85 = 8500 |
| 18) | 28 * 137 - 28 * 37 = | | 18) ( 137 - 37) * 28 = 2800 |
| 19) | 90 * 172 - 90 * 72 = | | 19) ( 172 - 72) * 90 = 9000 |
| 20) | 25 * 21 + 21 * 75 = | | 20) ( 25 + 75) * 21 = 2100 |
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Score: ______________ | |
