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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 489 · 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, 7 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 5, 5 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, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  4. 4.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  6. 6.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  9. 9.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  10. 10.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  11. 11.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  12. 12.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  13. 13.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?
  14. 14.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?
  15. 15.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  16. 16.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?
  17. 17.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  18. 18.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  19. 19.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?
  20. 20.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  26. 26.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?
  27. 27.A leapfrog list starts 6, 3 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 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  30. 30.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  31. 31.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?
  32. 32.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  33. 33.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 781
  2. 715
  3. 616
  4. 847
  5. 583
  6. 902
  7. 836
  8. 1067
  9. 407
  10. 902
  11. 572
  12. 506
  13. 506
  14. 143
  15. 528
  16. 748
  17. 924
  18. 737
  19. 946
  20. 781
  21. 1177
  22. 792
  23. 550
  24. 517
  25. 825
  26. 308
  27. 594
  28. 726
  29. 550
  30. 1001
  31. 1122
  32. 583
  33. 561
  34. 924
  35. 693
  36. 792
  37. 1012
  38. 451
  39. 583
  40. 1067

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