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 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 3.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 4.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 5.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 7.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 8.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 9.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 10.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 11.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.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?
- 13.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?
- 14.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
- 15.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 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.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 18.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 19.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 20.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 22.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?
- 23.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 24.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?
- 25.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 26.A leapfrog list starts 3, 7 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): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 28.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 29.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 30.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 31.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?
- 32.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 33.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 34.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 35.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?
- 36.A leapfrog list starts 1, 9 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 38.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 39.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
Answer key
- 671
- 1199
- 484
- 561
- 737
- 671
- 638
- 594
- 407
- 924
- 1122
- 583
- 231
- 1012
- 319
- 902
- 737
- 935
- 759
- 418
- 847
- 671
- 671
- 539
- 319
- 781
- 1122
- 451
- 363
- 484
- 341
- 198
- 1111
- 539
- 341
- 847
- 1056
- 1111
- 803
- 803
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