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.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 3.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 5.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.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?
- 7.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?
- 8.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 9.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 10.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 11.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 12.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
- 13.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 14.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 15.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?
- 16.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?
- 17.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 18.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.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?
- 20.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 21.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?
- 22.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?
- 23.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 24.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?
- 25.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 26.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 27.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?
- 28.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 30.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 31.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 32.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?
- 33.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?
- 34.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 35.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?
- 36.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 38.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 39.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?
- 40.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
Answer key
- 704
- 418
- 1177
- 539
- 583
- 396
- 781
- 1144
- 1023
- 572
- 528
- 429
- 858
- 979
- 462
- 1111
- 253
- 825
- 363
- 1001
- 143
- 891
- 924
- 671
- 341
- 550
- 253
- 1056
- 913
- 726
- 715
- 374
- 792
- 858
- 671
- 616
- 1177
- 462
- 638
- 748
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