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
- 1.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 2.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 3.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?
- 4.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 5.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 6.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?
- 7.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?
- 8.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?
- 9.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 10.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 11.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 12.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 13.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 14.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?
- 15.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?
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 18.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 19.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 20.A leapfrog list starts 1, 8 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, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 23.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?
- 24.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?
- 25.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 26.A leapfrog list starts 8, 6 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 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 30.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?
- 31.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 32.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 33.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?
- 34.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 35.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 36.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?
- 37.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 38.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 39.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 924
- 539
- 583
- 495
- 913
- 286
- 671
- 539
- 1056
- 517
- 1122
- 979
- 396
- 429
- 495
- 341
- 539
- 1199
- 572
- 759
- 847
- 231
- 517
- 924
- 781
- 968
- 1287
- 803
- 781
- 143
- 704
- 341
- 627
- 803
- 847
- 407
- 1023
- 715
- 869
- 902
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