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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 377 · 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 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  2. 2.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  3. 3.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  4. 4.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  5. 5.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?
  6. 6.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  7. 7.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  8. 8.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  13. 13.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  15. 15.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  16. 16.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  18. 18.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?
  19. 19.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  22. 22.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  23. 23.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?
  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 9, 5 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, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  27. 27.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?
  28. 28.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  30. 30.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  32. 32.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  33. 33.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?
  34. 34.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  37. 37.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  38. 38.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  39. 39.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  40. 40.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 143
  2. 539
  3. 462
  4. 968
  5. 319
  6. 198
  7. 605
  8. 847
  9. 143
  10. 517
  11. 748
  12. 660
  13. 1122
  14. 484
  15. 341
  16. 561
  17. 704
  18. 1012
  19. 396
  20. 979
  21. 693
  22. 715
  23. 374
  24. 968
  25. 935
  26. 374
  27. 528
  28. 561
  29. 616
  30. 462
  31. 308
  32. 781
  33. 671
  34. 913
  35. 286
  36. 473
  37. 858
  38. 814
  39. 1034
  40. 418

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