Leapfrog Sum Trick Worksheet
The trick (Seventh times eleven): A leapfrog list: start with two numbers, then each number is the sum of the two before it, up to 10 numbers. Find the 7th number. Multiply it by 11 (the number with a 0 on the end, plus the number): that is the total of all 10.
NameDateTime takenScore ___ / 40
- 1.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 2.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 3.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 4.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 5.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 6.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 7.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 8.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 9.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 10.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 11.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 12.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 13.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 15.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 16.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 17.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 18.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 20.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 21.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 22.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 23.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 25.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 26.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 27.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 29.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 30.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 32.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 33.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 34.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 35.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 36.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 38.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 39.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
Answer key
- 308
- 671
- 286
- 396
- 979
- 759
- 528
- 704
- 418
- 495
- 484
- 1089
- 528
- 605
- 1199
- 1034
- 869
- 1034
- 1001
- 935
- 583
- 561
- 891
- 726
- 880
- 583
- 374
- 517
- 1034
- 1199
- 539
- 473
- 1111
- 374
- 737
- 308
- 759
- 550
- 407
- 935
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