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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 922 · 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  4. 4.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  9. 9.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?
  10. 10.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  11. 11.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  13. 13.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  14. 14.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?
  15. 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  16. 16.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?
  17. 17.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  18. 18.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  19. 19.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  20. 20.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?
  21. 21.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  22. 22.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  25. 25.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  26. 26.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  27. 27.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?
  28. 28.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  29. 29.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  32. 32.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  33. 33.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?
  34. 34.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?
  35. 35.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  36. 36.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  37. 37.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?
  38. 38.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  40. 40.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 1056
  2. 1177
  3. 1034
  4. 1067
  5. 858
  6. 814
  7. 847
  8. 550
  9. 319
  10. 968
  11. 1232
  12. 528
  13. 880
  14. 528
  15. 198
  16. 880
  17. 803
  18. 1122
  19. 572
  20. 891
  21. 517
  22. 418
  23. 869
  24. 286
  25. 396
  26. 660
  27. 902
  28. 341
  29. 836
  30. 935
  31. 682
  32. 451
  33. 616
  34. 484
  35. 143
  36. 1001
  37. 1012
  38. 1089
  39. 781
  40. 1001

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