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.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?
- 2.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 3.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 4.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 5.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?
- 6.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 7.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 8.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 10.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?
- 11.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?
- 12.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 13.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?
- 14.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 15.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 16.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 17.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 18.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 19.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 20.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?
- 21.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 22.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 23.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?
- 24.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?
- 25.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 26.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?
- 27.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 28.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?
- 29.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 30.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?
- 31.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 32.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 33.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?
- 34.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 35.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 36.A leapfrog list starts 1, 5 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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 38.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 39.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
- 40.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
Answer key
- 451
- 957
- 825
- 319
- 429
- 539
- 517
- 1089
- 649
- 341
- 693
- 308
- 594
- 671
- 814
- 1199
- 1122
- 891
- 594
- 374
- 418
- 1089
- 506
- 550
- 1199
- 462
- 660
- 682
- 528
- 572
- 748
- 583
- 671
- 737
- 253
- 495
- 143
- 814
- 1232
- 198
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