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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 805 · 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 9, 3 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 6, 8 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, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.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?
  5. 5.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?
  6. 6.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  7. 7.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?
  8. 8.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  9. 9.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?
  10. 10.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  11. 11.A leapfrog list starts 9, 9 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 7, 9 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 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  16. 16.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  18. 18.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  19. 19.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 8, 2 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): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  25. 25.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  26. 26.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  27. 27.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  29. 29.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  30. 30.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?
  31. 31.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  32. 32.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?
  33. 33.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  34. 34.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  36. 36.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?
  37. 37.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  38. 38.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?
  39. 39.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 759
  2. 1034
  3. 550
  4. 1111
  5. 1034
  6. 913
  7. 418
  8. 1287
  9. 462
  10. 1067
  11. 1287
  12. 1177
  13. 748
  14. 1067
  15. 737
  16. 792
  17. 649
  18. 286
  19. 1089
  20. 605
  21. 616
  22. 979
  23. 231
  24. 539
  25. 561
  26. 1122
  27. 836
  28. 495
  29. 726
  30. 1012
  31. 231
  32. 935
  33. 1177
  34. 1199
  35. 1287
  36. 308
  37. 572
  38. 374
  39. 792
  40. 649

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