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
- 1.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 2.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 3.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 4.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 5.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?
- 6.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 7.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 8.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 9.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?
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 12.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 13.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 15.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 16.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 17.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?
- 18.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?
- 19.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 20.A leapfrog list starts 5, 8 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, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 22.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 23.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 25.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.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?
- 27.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 30.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 32.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 33.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?
- 34.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.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?
- 36.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 37.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 38.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 39.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 40.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 143
- 539
- 462
- 968
- 319
- 198
- 605
- 847
- 143
- 517
- 748
- 660
- 1122
- 484
- 341
- 561
- 704
- 1012
- 396
- 979
- 693
- 715
- 374
- 968
- 935
- 374
- 528
- 561
- 616
- 462
- 308
- 781
- 671
- 913
- 286
- 473
- 858
- 814
- 1034
- 418
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