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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 424 · 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): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  2. 2.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  3. 3.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  4. 4.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?
  5. 5.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?
  6. 6.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  7. 7.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  8. 8.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  9. 9.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  14. 14.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  15. 15.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  16. 16.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?
  17. 17.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?
  18. 18.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  19. 19.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  20. 20.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?
  21. 21.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  22. 22.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?
  23. 23.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  28. 28.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.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?
  30. 30.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  31. 31.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  32. 32.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  39. 39.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  40. 40.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 583
  2. 396
  3. 429
  4. 979
  5. 671
  6. 407
  7. 550
  8. 528
  9. 1111
  10. 627
  11. 671
  12. 935
  13. 462
  14. 781
  15. 638
  16. 847
  17. 550
  18. 968
  19. 858
  20. 1111
  21. 880
  22. 968
  23. 319
  24. 484
  25. 484
  26. 924
  27. 814
  28. 308
  29. 143
  30. 1034
  31. 308
  32. 946
  33. 396
  34. 913
  35. 616
  36. 671
  37. 913
  38. 143
  39. 605
  40. 869

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