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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 287 · 40 questions
TalentJR

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.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?
  2. 2.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  3. 3.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  7. 7.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  8. 8.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  9. 9.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?
  10. 10.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  11. 11.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?
  12. 12.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  13. 13.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?
  14. 14.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  15. 15.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  16. 16.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?
  17. 17.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  18. 18.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?
  19. 19.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  21. 21.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  22. 22.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  25. 25.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?
  26. 26.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  28. 28.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  29. 29.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?
  30. 30.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  33. 33.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  34. 34.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?
  35. 35.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  36. 36.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  37. 37.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.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?
  39. 39.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  40. 40.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 363
  2. 583
  3. 583
  4. 869
  5. 1232
  6. 792
  7. 418
  8. 1089
  9. 682
  10. 1232
  11. 1199
  12. 704
  13. 1001
  14. 858
  15. 627
  16. 539
  17. 143
  18. 583
  19. 363
  20. 759
  21. 308
  22. 396
  23. 1177
  24. 649
  25. 528
  26. 748
  27. 495
  28. 946
  29. 374
  30. 1067
  31. 429
  32. 231
  33. 1199
  34. 1144
  35. 924
  36. 638
  37. 484
  38. 671
  39. 506
  40. 363

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