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
- 1.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 2.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 3.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 4.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?
- 5.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 6.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?
- 7.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 8.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?
- 9.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?
- 10.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 11.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?
- 12.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 13.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 15.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 16.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 17.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?
- 18.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.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?
- 20.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.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?
- 22.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?
- 23.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 24.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 25.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?
- 26.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 27.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?
- 28.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 29.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.A leapfrog list starts 6, 2 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): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 33.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 34.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 35.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 36.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?
- 37.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?
- 38.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 39.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?
- 40.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
Answer key
- 1111
- 1287
- 517
- 803
- 869
- 1122
- 1144
- 363
- 495
- 1232
- 1089
- 473
- 451
- 286
- 704
- 594
- 594
- 517
- 143
- 407
- 748
- 627
- 825
- 825
- 341
- 396
- 231
- 682
- 231
- 979
- 506
- 781
- 605
- 715
- 374
- 847
- 341
- 484
- 704
- 1023
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