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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 517 · 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. 1.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  2. 2.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  3. 3.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  4. 4.A leapfrog list starts 5, 3 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 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  7. 7.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  8. 8.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  9. 9.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?
  10. 10.A leapfrog list starts 4, 9 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): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  12. 12.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  13. 13.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?
  14. 14.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  16. 16.A leapfrog list starts 3, 1 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, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  20. 20.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  21. 21.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  22. 22.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?
  23. 23.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  31. 31.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?
  32. 32.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  34. 34.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?
  35. 35.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?
  36. 36.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 539
  2. 649
  3. 1111
  4. 539
  5. 1067
  6. 781
  7. 891
  8. 759
  9. 979
  10. 1012
  11. 847
  12. 671
  13. 143
  14. 858
  15. 572
  16. 253
  17. 814
  18. 231
  19. 341
  20. 1122
  21. 1199
  22. 682
  23. 770
  24. 968
  25. 1144
  26. 814
  27. 550
  28. 946
  29. 616
  30. 253
  31. 572
  32. 627
  33. 891
  34. 1232
  35. 1089
  36. 748
  37. 583
  38. 693
  39. 1034
  40. 396

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