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.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 2.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 3.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 4.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 5.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 6.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 8.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?
- 9.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 11.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 12.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?
- 13.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?
- 14.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 15.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 16.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?
- 17.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 18.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 19.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 20.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 21.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 22.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 23.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 24.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 25.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 26.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?
- 27.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 28.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 29.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?
- 30.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 31.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?
- 32.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 34.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 35.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 36.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 37.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?
- 38.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 40.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
Answer key
- 286
- 319
- 231
- 286
- 880
- 638
- 363
- 550
- 506
- 638
- 429
- 605
- 660
- 506
- 1111
- 1067
- 1232
- 1199
- 451
- 143
- 363
- 748
- 594
- 814
- 1199
- 374
- 803
- 616
- 836
- 935
- 517
- 627
- 847
- 407
- 660
- 1177
- 429
- 473
- 1034
- 770
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