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): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 2.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 3.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 4.A leapfrog list starts 4, 1 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): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 6.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 7.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?
- 8.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 10.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?
- 11.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?
- 12.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 13.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.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?
- 15.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 16.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?
- 17.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?
- 18.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 19.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 21.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 22.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 23.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?
- 24.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 25.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 26.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?
- 27.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 28.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 29.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 30.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 31.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 33.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 34.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 36.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 37.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?
- 38.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 39.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 40.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
Answer key
- 495
- 616
- 1111
- 308
- 704
- 880
- 583
- 825
- 341
- 572
- 528
- 1177
- 198
- 341
- 374
- 539
- 308
- 858
- 759
- 550
- 814
- 792
- 869
- 935
- 605
- 418
- 759
- 539
- 418
- 979
- 957
- 198
- 396
- 1199
- 231
- 308
- 594
- 781
- 517
- 1089
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