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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 826 · 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): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  6. 6.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  7. 7.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  8. 8.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?
  9. 9.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  10. 10.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  14. 14.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?
  15. 15.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  18. 18.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  19. 19.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  21. 21.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  26. 26.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?
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  29. 29.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  31. 31.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  32. 32.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  33. 33.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  34. 34.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  35. 35.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  36. 36.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  37. 37.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?
  38. 38.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?
  39. 39.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  40. 40.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =

Answer key

  1. 814
  2. 341
  3. 726
  4. 286
  5. 473
  6. 935
  7. 902
  8. 374
  9. 891
  10. 1034
  11. 858
  12. 924
  13. 341
  14. 594
  15. 473
  16. 143
  17. 847
  18. 671
  19. 803
  20. 836
  21. 572
  22. 1034
  23. 473
  24. 462
  25. 1089
  26. 374
  27. 671
  28. 506
  29. 1001
  30. 660
  31. 253
  32. 792
  33. 319
  34. 363
  35. 418
  36. 627
  37. 517
  38. 1177
  39. 407
  40. 528

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