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
|
|
Thursday November 20 2025
07:10:58 AM | Thursday November 20 2025
07:10:58 AMFlip Answers |
| 1) | 407 * 393 = | | 1) 400 * 400 - 7 * 7 = 159951 |
| 2) | 90 * 110 = | | 2) 100 * 100 - 10 * 10 = 9900 |
| 3) | 410 * 390 = | | 3) 400 * 400 - 10 * 10 = 159900 |
| 4) | 309 * 291 = | | 4) 300 * 300 - 9 * 9 = 89919 |
| 5) | 208 * 192 = | | 5) 200 * 200 - 8 * 8 = 39936 |
| 6) | 207 * 193 = | | 6) 200 * 200 - 7 * 7 = 39951 |
| 7) | 398 * 402 = | | 7) 400 * 400 - 2 * 2 = 159996 |
| 8) | 295 * 305 = | | 8) 300 * 300 - 5 * 5 = 89975 |
| 9) | 209 * 191 = | | 9) 200 * 200 - 9 * 9 = 39919 |
| 10) | 390 * 410 = | | 10) 400 * 400 - 10 * 10 = 159900 |
| 11) | 144 * 25 - 25 * 44 = | | 11) ( 144 - 44) * 25 = 2500 |
| 12) | 89 * 248 - 48 * 89 = | | 12) ( 248 - 48) * 89 = 17800 |
| 13) | 43 * 60 + 40 * 43 = | | 13) ( 60 + 40) * 43 = 4300 |
| 14) | 72 * 265 - 65 * 72 = | | 14) ( 265 - 65) * 72 = 14400 |
| 15) | 67 * 171 - 71 * 67 = | | 15) ( 171 - 71) * 67 = 6700 |
| 16) | 149 * 62 + 51 * 62 = | | 16) ( 149 + 51) * 62 = 12400 |
| 17) | 48 * 259 - 48 * 59 = | | 17) ( 259 - 59) * 48 = 9600 |
| 18) | 51 * 81 + 81 * 149 = | | 18) ( 149 + 51) * 81 = 16200 |
| 19) | 69 * 141 - 69 * 41 = | | 19) ( 141 - 41) * 69 = 6900 |
| 20) | 91 * 256 - 91 * 56 = | | 20) ( 256 - 56) * 91 = 18200 |
|
Score: ______________ | |
