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 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 2.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?
- 3.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?
- 4.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 5.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?
- 6.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?
- 7.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 8.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?
- 9.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 10.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?
- 11.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 12.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 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 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 15.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?
- 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?
- 17.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 18.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 19.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?
- 20.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 21.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 22.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 23.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 25.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?
- 26.A leapfrog list starts 3, 7 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 5, 2 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): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
- 29.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.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?
- 31.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 32.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 33.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?
- 34.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 35.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 36.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?
- 37.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?
- 38.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 40.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
Answer key
- 1056
- 198
- 671
- 781
- 693
- 143
- 583
- 286
- 605
- 1089
- 726
- 880
- 737
- 616
- 594
- 396
- 671
- 539
- 484
- 1199
- 748
- 957
- 396
- 143
- 638
- 781
- 451
- 1067
- 759
- 517
- 451
- 1012
- 319
- 759
- 506
- 517
- 539
- 726
- 638
- 847
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