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.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?
- 2.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 3.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?
- 4.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 5.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 6.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?
- 7.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 8.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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?
- 11.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 12.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?
- 13.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 14.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 15.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 16.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 17.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 19.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 20.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 21.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 23.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 24.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 25.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?
- 26.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?
- 27.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?
- 28.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 29.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 30.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 31.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.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?
- 33.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 34.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?
- 35.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 36.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?
- 37.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.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?
- 39.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?
- 40.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
Answer key
- 1177
- 1089
- 748
- 759
- 396
- 253
- 484
- 627
- 682
- 374
- 583
- 143
- 605
- 429
- 561
- 737
- 363
- 1056
- 363
- 341
- 396
- 847
- 660
- 286
- 539
- 825
- 902
- 363
- 1232
- 1111
- 286
- 198
- 715
- 473
- 638
- 308
- 660
- 143
- 583
- 869
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