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): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 2.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 3.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 4.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?
- 5.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?
- 6.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 8.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 9.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 12.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 13.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 14.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 17.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.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?
- 19.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 21.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
- 22.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 23.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?
- 24.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?
- 25.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 26.A leapfrog list starts 2, 7 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 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 29.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 30.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 32.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 33.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 34.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?
- 35.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 37.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 38.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?
- 39.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 40.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
Answer key
- 759
- 770
- 286
- 682
- 583
- 506
- 1111
- 616
- 759
- 616
- 231
- 583
- 913
- 572
- 1111
- 902
- 649
- 429
- 770
- 979
- 1177
- 484
- 748
- 341
- 429
- 726
- 1177
- 825
- 1001
- 1067
- 792
- 638
- 781
- 968
- 1144
- 924
- 143
- 539
- 627
- 902
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