Math Main Page => Exercises - Math III
|
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
|
|
Saturday January 17 2026
06:09:55 AM | Saturday January 17 2026
06:09:55 AMFlip Answers |
| 1) | 401 * 399 = | | 1) 400 * 400 - 1 * 1 = 159999 |
| 2) | 101 * 99 = | | 2) 100 * 100 - 1 * 1 = 9999 |
| 3) | 295 * 305 = | | 3) 300 * 300 - 5 * 5 = 89975 |
| 4) | 208 * 192 = | | 4) 200 * 200 - 8 * 8 = 39936 |
| 5) | 390 * 410 = | | 5) 400 * 400 - 10 * 10 = 159900 |
| 6) | 406 * 394 = | | 6) 400 * 400 - 6 * 6 = 159964 |
| 7) | 393 * 407 = | | 7) 400 * 400 - 7 * 7 = 159951 |
| 8) | 194 * 206 = | | 8) 200 * 200 - 6 * 6 = 39964 |
| 9) | 207 * 193 = | | 9) 200 * 200 - 7 * 7 = 39951 |
| 10) | 404 * 396 = | | 10) 400 * 400 - 4 * 4 = 159984 |
| 11) | 270 * 64 - 64 * 70 = | | 11) ( 270 - 70) * 64 = 12800 |
| 12) | 62 * 272 - 62 * 72 = | | 12) ( 272 - 72) * 62 = 12400 |
| 13) | 60 * 145 - 60 * 45 = | | 13) ( 145 - 45) * 60 = 6000 |
| 14) | 43 * 61 + 43 * 139 = | | 14) ( 139 + 61) * 43 = 8600 |
| 15) | 238 * 80 - 80 * 38 = | | 15) ( 238 - 38) * 80 = 16000 |
| 16) | 35 * 23 + 65 * 23 = | | 16) ( 35 + 65) * 23 = 2300 |
| 17) | 40 * 32 + 32 * 160 = | | 17) ( 160 + 40) * 32 = 6400 |
| 18) | 173 * 58 - 73 * 58 = | | 18) ( 173 - 73) * 58 = 5800 |
| 19) | 53 * 26 + 147 * 26 = | | 19) ( 147 + 53) * 26 = 5200 |
| 20) | 43 * 97 + 97 * 157 = | | 20) ( 157 + 43) * 97 = 19400 |
|
Score: ______________ | |
