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
- 1.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 2.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 3.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 4.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 5.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?
- 6.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
- 7.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 8.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 9.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 11.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 12.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.A leapfrog list starts 9, 4 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, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
- 15.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 16.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 17.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 18.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 21.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. 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?
- 23.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 24.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 25.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 27.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.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?
- 29.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 30.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 31.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 33.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 34.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
- 35.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 36.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 37.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 39.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 40.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
Answer key
- 726
- 979
- 550
- 748
- 407
- 1067
- 1056
- 517
- 781
- 506
- 561
- 539
- 847
- 429
- 473
- 880
- 1001
- 594
- 517
- 1034
- 759
- 561
- 363
- 341
- 451
- 935
- 1067
- 528
- 594
- 473
- 649
- 770
- 1122
- 1012
- 374
- 231
- 671
- 484
- 396
- 693
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