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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 485 · 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 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  4. 4.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?
  5. 5.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  6. 6.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?
  7. 7.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  9. 9.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  14. 14.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  16. 16.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?
  17. 17.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  18. 18.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  19. 19.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?
  20. 20.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  21. 21.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  22. 22.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  26. 26.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?
  27. 27.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  28. 28.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  29. 29.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  32. 32.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?
  33. 33.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?
  34. 34.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 671
  2. 572
  3. 583
  4. 308
  5. 1122
  6. 781
  7. 528
  8. 825
  9. 572
  10. 462
  11. 1023
  12. 935
  13. 1089
  14. 451
  15. 594
  16. 616
  17. 198
  18. 693
  19. 143
  20. 319
  21. 143
  22. 198
  23. 583
  24. 671
  25. 847
  26. 143
  27. 979
  28. 814
  29. 759
  30. 1012
  31. 902
  32. 1067
  33. 374
  34. 1012
  35. 682
  36. 814
  37. 495
  38. 539
  39. 1023
  40. 847

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