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 Squaring Numbers

 Multiplying Numbers

  1. same 1st digit
  2. same 1st digit, sum 10
  3. same 2nd digit
  4. 3 digits, middle 0
  5. 3 digits, middle 1
  6. 3 digits, middle 2
  7. 3 digits, middle 3
  8. 3 digits, middle 4
  9. 3 digits, middle 5
  10. difference of 1
  11. difference of 2
  12. difference of 3
  13. difference of 4
  14. difference of 6
  15. difference of 8
  16. difference of 10
  17. 2 digits by 1 1/25
  18. 2 digits by 1.1
  19. 2 digits by 1 1/9
  20. 2 digits by 1 1/8
  21. 2 digits by 1 1/7
  22. 2 digits by 1 1/6
  23. 2 digits by 1 1/5
  24. 2 digits by 1 2/9
  25. 2 digits by 1 1/4
  26. 2 digits by 1 2/7
  27. 2 digits by 1.3
  28. 2 digits by 1 1/3
  29. 2 digits by 1 3/8
  30. 2 digits by 1 2/5
  31. 2 digits by 1 3/7
  32. 2 digits by 1 1/2
  33. 2 digits by 1 4/7
  34. 2 digits by 1 3/5
  35. 2 digits by 1.6
  36. 2,3 digits by 1 2/3
  37. 2 digits by 1 5/7
  38. 2 digits by 1 3/4
  39. 2 digits by 1 4/5
  40. 2 digits by 1 5/6
  41. 2 digits by 1 6/7
  42. 2 digits by 1.9
  43. 2 digits by 2.1
  44. 2 digits by 2 1/9
  45. 2 digits by 2 1/7
  46. 2 digits by 2 1/5
  47. 2 digits by 2 2/9
  48. 2 digits by 2 1/4
  49. 2 digits by 2.3
  50. 2 digits by 2 1/3
  51. 2 digits by 2 3/8
  52. 2 digits by 2 2/5
  53. 2 digits by 2.4
  54. 2 digits by 2 4/9
  55. 2, 3 digits by 2 1/2
  56. 2 digits by 2 4/7
  57. 2 digits by 2.6
  58. 2 digits by 2 5/8
  59. 2 digits by 2 2/3
  60. 2 digits by 2.7
  61. 2 digits by 2 5/7
  62. 2 digits by 2 3/4
  63. 2 digits by 2.8
  64. 2 digits by 2 7/9
  65. 2 digits by 2 6/7
  66. 2 digits by 2.9
  67. 2 digits by 3.1
  68. 2 digits by 3 1/8
  69. 2 digits by 3 1/7
  70. 2 digits by 3 1/6
  71. 2 digits by 3.2
  72. 2 digits by 3 2/9
  73. 2 digits by 3 1/4
  74. 2 digits by 3 1/3
  75. 2 digits by 3.4
  76. 2 digits by 3 3/7
  77. 2 digits by 3 4/9
  78. 2 digits by 3 1/2
  79. 2 digits by 3.6
  80. 2 digits by 3 4/7
  81. 2 digits by 3 5/8
  82. 2 digits by 3 2/3
  83. 2 digits by 3.7
  84. 2 digits by 3 5/7
  85. 2 digits by 3 3/4
  86. 2 digits by 3 4/5
  87. 2 digits by 3 6/7
  88. 2 digits by 3 7/8
  89. 2 digits by 3.9
  90. 2 digits by 4.1
  91. 2 digits by 4 1/4
  92. 2 digits by 4 1/7
  93. 2 digits by 4 1/6
  94. 2 digits by 4 1/5
  95. 2 digits by 4 2/7
  96. 2 digits by 4.3
  97. 2 digits by 4.4
  98. 2 digits by 4 3/7
  99. 2 digits by 4 4/9
  100. 2 digits by 4 1/2
  101. 2 digits by 4 5/9
  102. 2 digits by 4.6
  103. 2 digits by 4.7
  104. 2 digits by 4 3/4
  105. 2 digits by 4 4/5
  106. 2 digits by 4 5/6
  107. 2 digits by 4 7/8
  108. 2 digits by 5.1
  109. 2 digits by 5 1/8
  110. 2 digits by 5 1/6
  111. 2 digits by 5.2
  112. 2 digits by 5 1/4
  113. 2 digits by 5.3
  114. 2 digits by 5 4/9
  115. 2 digits by 5 1/2
  116. 2 digits by 5 5/9
  117. 2 digits by 5.6
  118. 2 digits by 5.7
  119. 2 digits by 5 4/7
  120. 2 digits by 5 5/7
  121. 2 digits by 5 4/5
  122. 2 digits by 5 6/7
  123. 2 digits by 5.9
  124. 2 digits by 6.1
  125. 2 digits by 6 1/8
  126. 2 digits by 6 1/5
  127. 2 digits by 6 1/4
  128. 2 digits by 6.3
  129. 2 digits by 6 1/3
  130. 2 digits by 6 3/8
  131. 2 digits by 6.4
  132. 2 digits by 6 4/9
  133. 2 digits by 6 1/2
  134. 2 digits by 6 5/9
  135. 2 digits by 6.6
  136. 2 digits by 6 2/3
  137. 2 digits by 6 7/9
  138. 2 digits by 6 5/6
  139. 2 digits by 6 6/7
  140. 2 digits by 6 8/9
  141. 2 digits by 7.1
  142. 2 digits by 7 1/7
  143. 2 digits by 7.2
  144. 2 digits by 7 1/4
  145. 2 digits by 7.3
  146. 2 digits by 7 2/7
  147. 2 digits by 7.4
  148. 2 digits by 7 1/2
  149. 2 digits by 7 3/5
  150. 2 digits by 7.6
  151. 2 digits by 7.7
  152. 2 digits by 7 3/4
  153. 2 digits by 7 4/5
  154. 2 digits by 8.1
  155. 2 digits by 8 1/6
  156. 2 digits by 8.2
  157. 2 digits by 8 2/7
  158. 2 digits by 8.3
  159. 2 digits by 8 1/3
  160. 2 digits by 8 3/7
  161. 2 digits by 8 4/7
  162. 2 digits by 8 1/2
  163. 2 digits by 8.6
  164. 2 digits by 8 5/8
  165. 2 digits by 8 2/3
  166. 2 digits by 8 5/7
  167. 2 digits by 8 7/9
  168. 2 digits by 8 7/8
  169. 2 digits by 8 8/9
  170. 2 digits by 9.1
  171. 2 digits by 9.2
  172. 2 digits by 9.3
  173. 2 digits by 9 1/3
  174. 2 digits by 9.4
  175. 2 digits by 9 1/2 (four steps)
  176. 2 digits by 9 1/2 (two steps)
  177. 2 digits by 9.6
  178. 2 digits by 9 2/3
  179. 2 digits by 9 5/7
  180. 2 digits by 9.7
  181. 2 digits by 9 3/4
  182. 2 digits by 9 7/9
  183. 2 digits by 9 4/5
  184. 2 digits by 9 5/6
  185. 2 digits by 9 6/7
  186. 2 digits by 9 7/8
  187. 2 digits by 9 8/9
  188. 2 digits by 10.1
  189. 2 digits by 10.4
  190. 2 digits by 10.7
  191. 2 digits by 10 1/2
  192. 2 digits by 11 1/2
  193. 2 digits by 12 1/2
  194. 2 digits by 15
  195. 2,3 digits by 16 2/3
  196. 2 digits by 18
  197. 2 digits by 19 1/2
  198. 2 digits by 20 1/2
  199. 2 digits by 21
  200. 2 digits by 22
  201. 2 digits by 23
  202. 2 digits by 24
  203. 2,3 digits by 25
  204. 2 digits by 26
  205. 2 digits by 27
  206. 2 digits by 28
  207. 2 digits by 29
  208. 2 digits by 29 1/2
  209. 2 digits by 30 1/2
  210. 2 digits by 31
  211. 2 digits by 32
  212. 2 digits by 33
  213. 2 digits by 33 1/3
  214. 2 digits by 34
  215. 2 digits by 35
  216. 2 digits by 36
  217. 2 digits by 37
  218. 2 digits by 37 1/2
  219. 2 digits by 38
  220. 2 digits by 39
  221. 2 digits by 39 1/2
  222. 2 digits by 40 1/2
  223. 2 digits by 42
  224. 2 digits by 43
  225. 2 digits by 44
  226. 2 digits by 45
  227. 2 digits by 46
  228. 2 digits by 47
  229. 2 digits by 48
  230. 2 digits by 49 (a)
  231. 2 digits by 49 (b)
  232. 2 digits by 49 1/2
  233. 2 digits by 50 1/2
  234. 2 digits by 51
  235. 2 digits by 52
  236. 2 digits by 53
  237. 2 digits by 54
  238. 2 digits by 55 (a)
  239. 2 digits by 55 (b)
  240. 2 digits by 56
  241. 2 digits by 57
  242. 2 digits by 58
  243. 2 digits by 59
  244. 2 digits by 59 1/2
  245. 2 digits by 60 1/2
  246. 2 digits by 61
  247. 2 digits by 62
  248. 2 digits by 63
  249. 2 digits by 64
  250. 2 digits by 65
  251. 2 digits by 66
  252. 2 digits by 67
  253. 2 digits by 68
  254. 2 digits by 69
  255. 2 digits by 69 1/2
  256. 2 digits by 70 1/2
  257. 2 digits by 71
  258. 2 digits by 72
  259. 2 digits by 73
  260. 2 digits by 74
  261. 2,3 digits by 75
  262. 2 digits by 76
  263. 2 digits by 77
  264. 2 digits by 78
  265. 2 digits by 79
  266. 2 digits by 79 1/2
  267. 2 digits by 80 1/2
  268. 2 digits by 81
  269. 2 digits by 82
  270. 2 digits by 83
  271. 2 digits by 84
  272. 2 digits by 85
  273. 2 digits by 86
  274. 2 digits by 87
  275. 2 digits by 88
  276. 2 digits by 89
  277. 2 digits by 89 1/2
  278. 2 digits by 90 1/2
  279. 2 digits by 91
  280. 2 digits by 92
  281. 2 digits by 93
  282. 2 digits by 94
  283. 2 digits by 97
  284. 2 digits by 99
  285. 3 digits by 99
  286. 2,3 digits by 101
  287. 2 digits by 102 + 11
  288. 2 digits by 103 + 12
  289. 2 digits by 125
  290. 3 digits by 143
  291. 2 digits by 166 2/3
  292. 2 digits by 198
  293. 2 digits by 201 + 11
  294. 2 digits by 202 + 11
  295. 2 digits by 250
  296. 2 digits by 297
  297. 2 digits by 375
  298. 2 digits by 396
  299. 2 digits by 495
  300. 2 digits by 594
  301. 2 digits by 625
  302. 2 digits by 693
  303. 2 digits by 792
  304. 2 digits by 875
  305. 2 digits by 891
  306. 2 digits by 999
  307. 2,3 digits by 1001 + 21,201
  308. 2-4 digits by 1000, + 21, 201, 2001
  309. 2-5 digits by 100001
  310. 1 rep. by 9 rep.
  311. 1 rep. by 12 rep.
  312. 1 rep. by 13 rep.
  313. 1 rep. by 14 rep.
  314. 1 rep. by 15 rep.
  315. 1 rep. by 16 rep.
  316. 1 rep. by 17 rep.
  317. 1 rep. by 18 rep.
  318. 1 rep. by 19 rep.
  319. 1 rep. by 21
  320. 1 rep. by 22
  321. 1 rep. by 23
  322. 1 rep. by 24
  323. 1 rep. by 25
  324. 1 rep. by 26
  325. 1 rep. by 27
  326. 1 rep. by 29
  327. 1 rep. by 33
  328. 1 rep. by 41
  329. 1 rep. by 44
  330. 1 rep. by 45
  331. 1 rep. by 55
  332. 1 rep. by 66
  333. 1 rep. by 77
  334. 1 rep. by 88
  335. 1 rep. by 99
  336. 1 rep. by 222
  337. 1 rep. by 333
  338. 2 rep. by 5 rep.
  339. 2 rep. by 9 rep.
  340. 2 rep. by 12
  341. 2 rep. by 13
  342. 2 rep. by 14
  343. 2 rep. by 15
  344. 2 rep. by 16
  345. 2 rep. by 17
  346. 2 rep. by 22
  347. 2 rep. by 24
  348. 2 rep. by 28
  349. 2 rep. by 33
  350. 2 rep. by 44
  351. 2 rep. by 45
  352. 2 rep. by 55
  353. 2 rep. by 66
  354. 2 rep. by 77
  355. 2 rep. by 88
  356. 2 rep. by 99
  357. 3 rep. by 6 rep.
  358. 3 rep. by 9 rep.
  359. 3 rep. by 13
  360. 3 rep. by 15
  361. 3 rep. by 23
  362. 3 rep. by 35
  363. 3 rep. by 55
  364. 3 rep. by 66
  365. 3 rep. by 77
  366. 3 rep. by 88
  367. 3 rep. by 99
  368. 4 rep. by 15
  369. 4 rep. by 17
  370. 4 rep. by 22
  371. 4 rep. by 24
  372. 4 rep. by 28
  373. 4 rep. by 31
  374. 4 rep. by 36
  375. 4 rep. by 42
  376. 4 rep. by 44
  377. 4 rep. by 55
  378. 4 rep. by 88
  379. 4 rep. by 3 rep.
  380. 4 rep. by 5 rep.
  381. 4 rep. by 9 rep.
  382. 5 rep. by 25
  383. 5 rep. by 28
  384. 5 rep. by 33
  385. 5 rep. by 55
  386. 5 rep. by 66
  387. 5 rep. by 88
  388. 5 rep. by 9 rep.
  389. 6 rep. by 9 rep.
  390. 6 rep. by 12
  391. 6 rep. by 16
  392. 6 rep. by 22
  393. 6 rep. by 31
  394. 6 rep. by 32
  395. 6 rep. by 33
  396. 6 rep. by 43
  397. 6 rep. by 66
  398. 6 rep. by 77
  399. 6 rep. by 88
  400. 6 rep. by 444
  401. 6 rep. by 888
  402. 7 rep. by 9 rep.
  403. 7 rep. by 17
  404. 7 rep. by 32
  405. 7 rep. by 33
  406. 7 rep. by 42
  407. 7 rep. by 44
  408. 7 rep. by 55
  409. 7 rep. by 88
  410. 8 rep. by 9 rep.
  411. 8 rep. by 22
  412. 8 rep. by 23
  413. 8 rep. by 29
  414. 8 rep. by 36
  415. 8 rep. by 44
  416. 8 rep. by 55
  417. 8 rep. by 66
  418. 8 rep. by 88
  419. 9 rep. by 14
  420. 9 rep. by 22
  421. 9 rep. by 25
  422. 9 rep. by 27
  423. 9 rep. by 33
  424. 9 rep. by 44
  425. 9 rep. by 55
  426. 9 rep. by 77
  427. 9 rep. by 99
  428. 3 repeating by 2, /37
  429. 3 repeating by 5, /37
  430. 9 rep. by 3, /12345679
  431. multi-digits by 8 + last digit
  432. by 8, add number, - 20
  433. integer + 1/2 times, + 1
  434. sum,difference of 2,1 digits
  435. two mixed numbers
  436. two mixed numbers,fractions
  437. 4 digits by 99
  438. 4 digits by 137, then 73; -1200
  439. 5 digits by 9091, then 11; -1200

 Dividing Numbers

 Adding Numbers

 Subtracting Numbers

 Finding Percents

Calculation
Practice Exercises

Full List


   Multiplying a 2-digit number by 2 1/7

  1. Multiply the number by 5.
  2. Multiply this product by 3.
  3. Divide by 7.

   Example:

  1. If the 2-digit number chosen to multiply by 2 1/7 is 21:
  2. Multiply by 5: 5 × 21 = 105.
  3. Multiply this product by 3: 3 × 105 = 315.
  4. Divide by 7: 315/7 = 45.
  5. So 2 1/7 × 21 = 45.

   See the pattern?

  1. If the 2-digit number chosen to multiply by 2 1/7 is 54:
  2. Multiply by 5: 5 × 54 = 250 + 20 = 270.
  3. Multiply this product by 3: 3 × 270 = 600 + 210 = 810.
  4. Divide by 7: 810/7 = 115 5/7.
  5. So 2 1/7 × 54 = 115 5/7.


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