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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 890 · 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.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.A leapfrog list starts 9, 1 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  4. 4.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  5. 5.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?
  6. 6.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  7. 7.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  12. 12.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?
  13. 13.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  16. 16.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?
  17. 17.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  19. 19.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  20. 20.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  21. 21.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?
  22. 22.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  23. 23.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  26. 26.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  31. 31.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  36. 36.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  37. 37.A leapfrog list starts 5, 4 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 3, 2 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, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  40. 40.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =

Answer key

  1. 517
  2. 583
  3. 1056
  4. 308
  5. 506
  6. 605
  7. 660
  8. 759
  9. 484
  10. 979
  11. 1177
  12. 539
  13. 1023
  14. 308
  15. 396
  16. 924
  17. 759
  18. 1177
  19. 671
  20. 902
  21. 506
  22. 968
  23. 693
  24. 418
  25. 671
  26. 979
  27. 143
  28. 891
  29. 880
  30. 198
  31. 957
  32. 979
  33. 550
  34. 858
  35. 517
  36. 374
  37. 627
  38. 341
  39. 462
  40. 1111

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