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
- 1.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 2.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 3.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?
- 4.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?
- 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?
- 6.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 7.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?
- 8.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?
- 9.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 10.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 11.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 12.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 13.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?
- 14.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 15.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 17.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 18.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 19.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?
- 20.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 21.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 22.A leapfrog list starts 5, 8 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 4, 3 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 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 26.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 27.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?
- 28.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?
- 29.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 30.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?
- 31.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 32.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?
- 33.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 34.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 35.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 36.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 37.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 38.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?
- 39.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?
- 40.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
Answer key
- 825
- 891
- 561
- 407
- 462
- 539
- 1067
- 286
- 594
- 231
- 1034
- 363
- 1001
- 407
- 462
- 869
- 891
- 1089
- 649
- 451
- 528
- 979
- 484
- 418
- 814
- 286
- 781
- 638
- 671
- 847
- 495
- 550
- 737
- 506
- 561
- 495
- 572
- 550
- 517
- 1122
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