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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 61 · 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. 1.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  2. 2.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  3. 3.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  5. 5.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  6. 6.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?
  7. 7.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  10. 10.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?
  11. 11.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.A leapfrog list starts 6, 2 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): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  14. 14.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?
  15. 15.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  17. 17.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  18. 18.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  19. 19.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  20. 20.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?
  21. 21.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  25. 25.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  26. 26.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  27. 27.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?
  28. 28.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  29. 29.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?
  30. 30.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  31. 31.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  33. 33.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  34. 34.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  37. 37.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  40. 40.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =

Answer key

  1. 847
  2. 473
  3. 957
  4. 319
  5. 1034
  6. 1111
  7. 286
  8. 682
  9. 396
  10. 847
  11. 671
  12. 506
  13. 759
  14. 902
  15. 660
  16. 506
  17. 671
  18. 308
  19. 1111
  20. 528
  21. 198
  22. 594
  23. 1232
  24. 748
  25. 924
  26. 1089
  27. 1232
  28. 814
  29. 429
  30. 979
  31. 759
  32. 715
  33. 946
  34. 814
  35. 1177
  36. 517
  37. 198
  38. 550
  39. 198
  40. 759

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