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
- 1.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 2.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 3.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?
- 4.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 5.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 6.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 7.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?
- 8.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?
- 9.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
- 10.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 11.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 12.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 13.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 15.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 16.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 17.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 18.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 19.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?
- 20.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 21.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 22.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 23.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?
- 24.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 25.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?
- 26.A leapfrog list starts 8, 9 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 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 29.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?
- 30.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 31.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?
- 32.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 33.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 35.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?
- 36.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 37.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 38.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 39.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 528
- 704
- 319
- 869
- 583
- 572
- 1177
- 847
- 946
- 759
- 1089
- 902
- 550
- 979
- 935
- 880
- 451
- 1034
- 495
- 550
- 649
- 1199
- 869
- 1023
- 583
- 1232
- 319
- 957
- 429
- 1034
- 627
- 836
- 374
- 396
- 825
- 924
- 561
- 605
- 528
- 946
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