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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 2.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?
- 3.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 5.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?
- 6.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 7.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.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?
- 9.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 10.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 11.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 13.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?
- 14.A leapfrog list starts 9, 2 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, 4 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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 18.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 19.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 20.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 21.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?
- 22.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 23.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 24.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 25.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 26.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 27.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 29.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 30.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 32.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 33.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 34.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?
- 35.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?
- 36.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 37.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 38.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?
- 39.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 40.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
Answer key
- 594
- 583
- 583
- 968
- 506
- 880
- 231
- 253
- 748
- 374
- 583
- 1067
- 572
- 671
- 748
- 517
- 143
- 429
- 660
- 814
- 341
- 726
- 506
- 671
- 891
- 616
- 1023
- 308
- 594
- 869
- 616
- 539
- 924
- 539
- 528
- 880
- 979
- 682
- 561
- 1287
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