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): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 2.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 3.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?
- 4.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 6.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 7.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 8.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 9.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 10.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?
- 11.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 12.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?
- 13.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 14.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 15.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 17.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 18.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?
- 19.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 20.A leapfrog list starts 8, 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): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 22.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?
- 23.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
- 24.A leapfrog list starts 1, 9 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): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 26.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 27.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?
- 28.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 30.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?
- 31.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 32.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?
- 33.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 34.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 35.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?
- 36.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 37.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?
- 38.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?
- 39.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 40.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
Answer key
- 1089
- 473
- 407
- 759
- 726
- 1089
- 803
- 660
- 363
- 319
- 913
- 737
- 473
- 495
- 902
- 231
- 341
- 539
- 374
- 792
- 517
- 506
- 671
- 847
- 1034
- 924
- 759
- 550
- 253
- 528
- 902
- 198
- 418
- 1034
- 143
- 748
- 363
- 231
- 517
- 1056
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