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
- 1.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 2.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?
- 3.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?
- 4.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?
- 5.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?
- 6.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 7.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 8.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?
- 9.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 12.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 13.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 14.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 16.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 17.A leapfrog list starts 8, 8 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 6, 2 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 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.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?
- 21.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 22.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?
- 23.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 24.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 25.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?
- 26.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 27.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 28.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 29.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 30.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?
- 31.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?
- 32.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 33.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 34.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?
- 35.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?
- 36.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.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?
- 39.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 40.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
Answer key
- 1089
- 517
- 748
- 594
- 374
- 616
- 803
- 704
- 1199
- 253
- 1111
- 1144
- 726
- 1023
- 451
- 968
- 1144
- 506
- 1232
- 759
- 671
- 528
- 363
- 770
- 814
- 638
- 748
- 814
- 1034
- 253
- 583
- 319
- 902
- 1056
- 143
- 1199
- 924
- 682
- 803
- 627
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