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
- 1.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 2.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 3.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 4.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?
- 5.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 6.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 7.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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?
- 9.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 10.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 11.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?
- 12.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 13.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?
- 14.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 15.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 18.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 19.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 20.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 21.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 22.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 26.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.A leapfrog list starts 4, 6 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 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 30.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 31.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 32.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?
- 33.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 34.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 35.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 36.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.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?
- 38.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 39.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?
- 40.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
Answer key
- 429
- 902
- 693
- 539
- 1089
- 924
- 231
- 704
- 451
- 1144
- 528
- 506
- 1012
- 341
- 704
- 891
- 660
- 627
- 638
- 726
- 836
- 1023
- 1287
- 286
- 924
- 319
- 748
- 660
- 583
- 803
- 660
- 561
- 374
- 583
- 396
- 1012
- 1067
- 462
- 979
- 880
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