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
- 1.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 2.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 3.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 4.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?
- 5.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 6.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?
- 7.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 8.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 9.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?
- 10.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 11.A leapfrog list starts 4, 6 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 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 14.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 15.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?
- 16.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?
- 17.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?
- 18.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 19.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 20.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 21.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 22.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?
- 23.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?
- 24.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 25.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 26.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 27.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 28.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.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?
- 30.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 31.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?
- 32.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 33.A leapfrog list starts 1, 5 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 7, 1 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 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 37.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 39.A leapfrog list starts 6, 3 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
Answer key
- 682
- 319
- 1144
- 726
- 572
- 946
- 594
- 286
- 748
- 704
- 748
- 429
- 231
- 407
- 418
- 396
- 286
- 539
- 770
- 693
- 462
- 671
- 561
- 979
- 550
- 1056
- 341
- 671
- 363
- 583
- 682
- 506
- 495
- 473
- 803
- 627
- 902
- 1287
- 594
- 1056
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