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
- 1.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 2.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 3.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.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?
- 5.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?
- 6.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?
- 7.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 8.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?
- 9.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?
- 10.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 11.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 12.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 13.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?
- 14.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 15.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?
- 16.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?
- 17.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 18.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 20.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 21.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 22.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 23.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 24.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 25.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 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?
- 27.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 28.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?
- 29.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 31.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 32.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
- 33.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?
- 34.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 35.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 36.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?
- 37.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?
- 38.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?
- 39.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?
- 40.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
Answer key
- 451
- 319
- 693
- 286
- 462
- 847
- 407
- 979
- 583
- 418
- 638
- 1122
- 1067
- 198
- 286
- 451
- 649
- 836
- 396
- 572
- 649
- 1056
- 1067
- 847
- 627
- 583
- 374
- 451
- 341
- 308
- 902
- 638
- 143
- 957
- 924
- 506
- 484
- 143
- 649
- 825
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