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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 619 · 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.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?
  2. 2.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  3. 3.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  4. 4.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  5. 5.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?
  6. 6.A leapfrog list starts 3, 1 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 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  11. 11.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  12. 12.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  13. 13.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  15. 15.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  21. 21.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  22. 22.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  24. 24.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?
  25. 25.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  26. 26.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?
  27. 27.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?
  28. 28.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  29. 29.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?
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  32. 32.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  33. 33.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  35. 35.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  36. 36.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  37. 37.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?
  38. 38.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  39. 39.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?
  40. 40.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =

Answer key

  1. 880
  2. 451
  3. 627
  4. 198
  5. 715
  6. 253
  7. 814
  8. 451
  9. 484
  10. 473
  11. 671
  12. 418
  13. 231
  14. 957
  15. 319
  16. 979
  17. 935
  18. 968
  19. 803
  20. 803
  21. 957
  22. 616
  23. 396
  24. 616
  25. 286
  26. 1012
  27. 924
  28. 528
  29. 1034
  30. 143
  31. 418
  32. 605
  33. 495
  34. 594
  35. 407
  36. 759
  37. 737
  38. 396
  39. 891
  40. 253

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