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
- 1.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 2.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 3.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?
- 4.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 5.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 7.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 9.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 10.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 11.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 12.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?
- 13.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 14.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?
- 15.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 16.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?
- 17.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?
- 18.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 19.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?
- 20.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?
- 21.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 22.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 23.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 24.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 25.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 26.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 27.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 29.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 30.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 31.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?
- 32.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 33.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 35.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 36.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 38.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?
- 39.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?
- 40.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
Answer key
- 462
- 231
- 1012
- 869
- 704
- 308
- 253
- 1122
- 825
- 781
- 1287
- 572
- 253
- 473
- 748
- 429
- 517
- 671
- 561
- 781
- 1111
- 935
- 341
- 891
- 1034
- 429
- 880
- 616
- 770
- 682
- 539
- 946
- 561
- 286
- 660
- 946
- 924
- 341
- 143
- 902
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