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): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 2.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 3.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 4.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?
- 5.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 6.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?
- 7.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 8.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 9.A leapfrog list starts 8, 5 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): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 11.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?
- 12.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 14.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 15.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 16.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 17.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?
- 18.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?
- 19.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?
- 20.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 21.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 22.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?
- 23.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 24.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?
- 25.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?
- 26.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?
- 27.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 28.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 29.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 30.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 31.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 32.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?
- 33.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?
- 34.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 35.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.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?
- 37.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 38.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 40.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?
Answer key
- 781
- 715
- 726
- 1012
- 902
- 737
- 506
- 1144
- 880
- 671
- 759
- 693
- 748
- 198
- 847
- 638
- 627
- 1023
- 1122
- 1089
- 1122
- 869
- 462
- 748
- 561
- 594
- 550
- 847
- 363
- 308
- 1067
- 814
- 869
- 429
- 891
- 231
- 528
- 539
- 253
- 418
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