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 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 2.A leapfrog list starts 3, 8 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): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 4.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 5.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 6.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?
- 7.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 8.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?
- 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 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 11.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 12.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 13.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?
- 14.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 15.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 16.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?
- 17.A leapfrog list starts 4, 1 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 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 20.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 21.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?
- 22.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 23.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 24.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?
- 25.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 26.A leapfrog list starts 3, 1 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 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 29.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
- 30.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 31.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?
- 32.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 33.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 34.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 35.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 36.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 37.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 38.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 39.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?
- 40.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
Answer key
- 1232
- 869
- 847
- 286
- 451
- 803
- 814
- 671
- 946
- 495
- 583
- 583
- 737
- 880
- 1111
- 484
- 308
- 737
- 572
- 1287
- 231
- 660
- 1067
- 495
- 506
- 253
- 660
- 759
- 429
- 374
- 704
- 374
- 429
- 594
- 539
- 605
- 528
- 693
- 748
- 671
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