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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 388 · 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.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?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  4. 4.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  5. 5.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  6. 6.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  9. 9.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  10. 10.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  11. 11.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  12. 12.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  13. 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. 14.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  18. 18.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  19. 19.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  24. 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. 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. 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. 27.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  28. 28.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  29. 29.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?
  30. 30.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?
  31. 31.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  32. 32.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  33. 33.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  37. 37.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?
  38. 38.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  39. 39.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  40. 40.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =

Answer key

  1. 550
  2. 825
  3. 979
  4. 539
  5. 341
  6. 517
  7. 858
  8. 418
  9. 231
  10. 715
  11. 660
  12. 506
  13. 1122
  14. 583
  15. 847
  16. 616
  17. 902
  18. 726
  19. 1034
  20. 649
  21. 671
  22. 737
  23. 363
  24. 847
  25. 814
  26. 374
  27. 572
  28. 693
  29. 902
  30. 759
  31. 759
  32. 319
  33. 1177
  34. 418
  35. 880
  36. 396
  37. 418
  38. 1122
  39. 198
  40. 847

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