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
- 1.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 2.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 3.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
- 4.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?
- 5.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 6.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?
- 7.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?
- 8.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?
- 9.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?
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 12.A leapfrog list starts 3, 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 8, 2 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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 15.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 16.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 17.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.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?
- 19.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?
- 20.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 23.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
- 24.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?
- 25.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 26.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 27.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 28.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 29.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 30.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 33.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 34.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 35.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 36.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?
- 37.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?
- 38.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?
- 39.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 40.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
Answer key
- 847
- 891
- 946
- 627
- 1144
- 1012
- 1034
- 693
- 319
- 286
- 737
- 429
- 616
- 143
- 803
- 924
- 550
- 891
- 627
- 605
- 143
- 693
- 671
- 374
- 616
- 1056
- 484
- 462
- 506
- 484
- 1001
- 231
- 704
- 1089
- 1177
- 473
- 539
- 781
- 979
- 748
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