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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 2.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 3.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?
- 4.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 5.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?
- 6.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?
- 7.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 8.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?
- 9.A leapfrog list starts 2, 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): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 11.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 12.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 13.A leapfrog list starts 7, 2 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): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 16.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 17.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 18.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?
- 19.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 20.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 21.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 23.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?
- 24.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 25.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?
- 26.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 27.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 28.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?
- 29.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?
- 30.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 31.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 32.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.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?
- 35.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 36.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?
- 37.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
- 38.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?
- 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 40.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
Answer key
- 143
- 374
- 1177
- 583
- 319
- 902
- 902
- 627
- 462
- 561
- 286
- 308
- 561
- 726
- 198
- 759
- 1199
- 836
- 1232
- 649
- 924
- 363
- 682
- 1012
- 1023
- 1001
- 418
- 1012
- 737
- 484
- 1177
- 1089
- 1056
- 319
- 429
- 880
- 638
- 946
- 616
- 715
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