30 x 30 Table for Squares
Students and also many adults like myself were compelled to learn a multiplication table and to know perfect squares up to 12². A student who is able to memorize squares up to 30² will be way ahead of other students. Even learning up to 20²
Lets see if we can learn up to a 20². You have a these numbers 169, 196, 225, 256, 289, 324, 361, and 400. We are going to memorize one number and that is 13²=169.
So we start with 169 and we then reverse the 2 digits and have 196.
We also understand that all numbers that end in 5 always end in 25. If 14² is 196, then 15² will be larger than 200 so 15²=225.
We take the last 2 digits and move them to the front. So 225 becomes 25x and 16² has a units digit of 6 so 16²=256.
17² is 289 and the last two digits add up to 17.
324 is 2 3 4 a numerical procession with 2 and 3 reversed.
361 3+6=9 so if we add them together in our number we have 91. We flip these around and we have 19.
Another quick way is that the front numbers progress by 3 from 169 3 times and then progress by 4. The units digit always follows the square of the units digit.
169 196 225 256 289 324 369 400
400 is easy.
There are many people who will contend that there are fast ways to figure out squares and there are but if a person is able to memorize the table to a 20 x 20 (30 x 30 is even better) they will be incredible mathematicians. Concepts like long division, factoring polynomials, logarithms, trigonometry, and basic algebra will be easier. Advanced math like many integration theorems, Greens Theorem and Fourier Transforms will all be easier if person understands numbers beyond the 10 by 10 multiplication table. People will also understand and retain this information for life time instead of just forgetting about it when they leave academia.
We also understand that all numbers that end in 5 always end in 25. If 14² is 196, then 15² will be larger than 200 so 15²=225.
We take the last 2 digits and move them to the front. So 225 becomes 25x and 16² has a units digit of 6 so 16²=256.
17² is 289 and the last two digits add up to 17.
324 is 2 3 4 a numerical procession with 2 and 3 reversed.
361 3+6=9 so if we add them together in our number we have 91. We flip these around and we have 19.
Another quick way is that the front numbers progress by 3 from 169 3 times and then progress by 4. The units digit always follows the square of the units digit.
169 196 225 256 289 324 369 400
400 is easy.
There are many people who will contend that there are fast ways to figure out squares and there are but if a person is able to memorize the table to a 20 x 20 (30 x 30 is even better) they will be incredible mathematicians. Concepts like long division, factoring polynomials, logarithms, trigonometry, and basic algebra will be easier. Advanced math like many integration theorems, Greens Theorem and Fourier Transforms will all be easier if person understands numbers beyond the 10 by 10 multiplication table. People will also understand and retain this information for life time instead of just forgetting about it when they leave academia.
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1 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
2 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | 24 | 26 | 28 | 30 | 32 | 34 | 36 | 38 | 40 | 42 | 44 | 46 | 48 | 50 | 52 | 54 | 56 | 58 | 60 |
3 | 3 | 6 | 9 | 12 | 15 | 18 | 21 | 24 | 27 | 30 | 33 | 36 | 39 | 42 | 45 | 48 | 51 | 54 | 57 | 60 | 63 | 66 | 69 | 72 | 75 | 78 | 81 | 84 | 87 | 90 |
4 | 4 | 8 | 12 | 16 | 20 | 24 | 28 | 32 | 36 | 40 | 44 | 48 | 52 | 56 | 60 | 64 | 68 | 72 | 76 | 80 | 84 | 88 | 92 | 96 | 100 | 104 | 108 | 112 | 116 | 120 |
5 | 5 | 10 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 | 55 | 60 | 65 | 70 | 75 | 80 | 85 | 90 | 95 | 100 | 105 | 110 | 215 | 120 | 125 | 130 | 135 | 140 | 145 | 150 |
6 | 6 | 12 | 18 | 24 | 30 | 36 | 42 | 48 | 54 | 60 | 66 | 72 | 78 | 84 | 90 | 96 | 102 | 108 | 114 | 120 | 126 | 132 | 238 | 144 | 150 | 156 | 162 | 168 | 174 | 180 |
7 | 7 | 14 | 21 | 28 | 35 | 42 | 49 | 56 | 63 | 70 | 77 | 84 | 91 | 98 | 105 | 112 | 119 | 126 | 133 | 140 | 147 | 154 | 261 | 168 | 175 | 182 | 189 | 196 | 203 | 210 |
8 | 8 | 16 | 24 | 32 | 40 | 48 | 56 | 64 | 72 | 80 | 88 | 96 | 104 | 112 | 120 | 128 | 136 | 144 | 152 | 160 | 168 | 176 | 285 | 192 | 200 | 208 | 216 | 224 | 232 | 240 |
9 | 9 | 18 | 27 | 36 | 45 | 54 | 63 | 72 | 81 | 90 | 99 | 108 | 117 | 126 | 135 | 144 | 153 | 162 | 171 | 180 | 189 | 208 | 308 | 216 | 225 | 234 | 243 | 252 | 261 | 270 |
10 | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | 110 | 120 | 130 | 140 | 150 | 160 | 170 | 180 | 190 | 200 | 210 | 220 | 230 | 240 | 250 | 260 | 270 | 280 | 290 | 300 |
11 | 11 | 22 | 33 | 44 | 55 | 66 | 77 | 88 | 99 | 110 | 121 | 132 | 143 | 154 | 165 | 176 | 187 | 198 | 209 | 220 | 231 | 242 | 253 | 264 | 275 | 286 | 297 | 308 | 319 | 330 |
12 | 12 | 24 | 36 | 48 | 60 | 72 | 84 | 96 | 108 | 120 | 132 | 144 | 156 | 168 | 180 | 192 | 204 | 216 | 228 | 240 | 252 | 264 | 276 | 288 | 300 | 312 | 324 | 336 | 348 | 360 |
13 | 13 | 26 | 39 | 52 | 65 | 78 | 91 | 104 | 117 | 130 | 143 | 156 | 169 | 182 | 195 | 208 | 221 | 234 | 247 | 260 | 273 | 286 | 299 | 312 | 325 | 338 | 351 | 364 | 377 | 390 |
14 | 14 | 28 | 42 | 56 | 70 | 84 | 98 | 112 | 126 | 140 | 154 | 168 | 182 | 196 | 210 | 224 | 238 | 252 | 266 | 280 | 294 | 308 | 322 | 336 | 350 | 364 | 378 | 392 | 406 | 420 |
15 | 15 | 30 | 45 | 60 | 75 | 90 | 105 | 120 | 135 | 150 | 165 | 180 | 195 | 210 | 225 | 240 | 255 | 270 | 285 | 300 | 315 | 330 | 345 | 360 | 375 | 390 | 405 | 420 | 435 | 450 |
16 | 16 | 32 | 48 | 64 | 80 | 96 | 112 | 128 | 144 | 160 | 176 | 192 | 208 | 224 | 240 | 256 | 272 | 288 | 304 | 320 | 336 | 252 | 368 | 384 | 400 | 416 | 432 | 448 | 464 | 480 |
17 | 17 | 34 | 51 | 68 | 85 | 102 | 119 | 136 | 153 | 170 | 187 | 204 | 221 | 238 | 255 | 272 | 289 | 306 | 323 | 340 | 357 | 274 | 391 | 408 | 425 | 442 | 459 | 476 | 493 | 510 |
18 | 18 | 36 | 54 | 72 | 90 | 108 | 126 | 144 | 162 | 180 | 198 | 216 | 234 | 252 | 270 | 288 | 306 | 324 | 342 | 360 | 378 | 296 | 414 | 432 | 450 | 468 | 486 | 504 | 522 | 540 |
19 | 19 | 38 | 57 | 76 | 95 | 114 | 133 | 152 | 171 | 190 | 209 | 228 | 247 | 266 | 285 | 304 | 323 | 342 | 361 | 380 | 399 | 318 | 437 | 456 | 475 | 492 | 513 | 532 | 551 | 570 |
20 | 20 | 40 | 60 | 80 | 100 | 120 | 140 | 160 | 180 | 200 | 220 | 240 | 260 | 280 | 300 | 320 | 340 | 360 | 380 | 400 | 420 | 440 | 460 | 480 | 500 | 518 | 540 | 560 | 580 | 600 |
21 | 21 | 42 | 63 | 84 | 105 | 126 | 147 | 168 | 189 | 210 | 231 | 252 | 273 | 294 | 315 | 336 | 357 | 378 | 399 | 420 | 441 | 462 | 483 | 504 | 525 | 542 | 567 | 588 | 609 | 630 |
22 | 22 | 44 | 66 | 88 | 110 | 132 | 154 | 176 | 208 | 220 | 242 | 264 | 286 | 308 | 330 | 252 | 274 | 296 | 318 | 440 | 462 | 484 | 506 | 528 | 550 | 572 | 594 | 616 | 638 | 660 |
23 | 23 | 46 | 69 | 92 | 215 | 238 | 261 | 285 | 308 | 230 | 253 | 276 | 299 | 322 | 345 | 368 | 391 | 414 | 437 | 460 | 483 | 506 | 529 | 552 | 575 | 595 | 618 | 641 | 667 | 690 |
24 | 24 | 48 | 72 | 96 | 120 | 144 | 168 | 192 | 216 | 240 | 264 | 288 | 312 | 336 | 360 | 384 | 408 | 432 | 456 | 480 | 504 | 528 | 552 | 576 | 600 | 624 | 648 | 672 | 696 | 720 |
25 | 25 | 50 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 | 300 | 325 | 350 | 375 | 400 | 425 | 450 | 475 | 500 | 525 | 550 | 575 | 600 | 625 | 650 | 618 | 700 | 725 | 750 |
26 | 26 | 52 | 78 | 104 | 130 | 156 | 182 | 208 | 234 | 260 | 286 | 312 | 338 | 364 | 390 | 416 | 442 | 468 | 494 | 520 | 546 | 572 | 595 | 624 | 650 | 676 | 702 | 728 | 754 | 780 |
27 | 27 | 54 | 81 | 108 | 135 | 162 | 189 | 216 | 243 | 270 | 297 | 324 | 351 | 378 | 405 | 432 | 459 | 486 | 513 | 540 | 567 | 594 | 618 | 648 | 675 | 702 | 729 | 756 | 783 | 810 |
28 | 28 | 56 | 84 | 112 | 140 | 168 | 196 | 224 | 252 | 280 | 308 | 336 | 364 | 392 | 420 | 448 | 476 | 504 | 532 | 560 | 588 | 616 | 641 | 672 | 700 | 728 | 756 | 784 | 812 | 840 |
29 | 29 | 58 | 87 | 116 | 145 | 174 | 203 | 232 | 261 | 290 | 319 | 348 | 377 | 406 | 435 | 464 | 493 | 522 | 551 | 580 | 609 | 638 | 667 | 696 | 725 | 754 | 783 | 812 | 841 | 870 |
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