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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 896 · 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 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  2. 2.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?
  3. 3.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  4. 4.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  7. 7.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  8. 8.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  9. 9.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?
  10. 10.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  11. 11.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?
  12. 12.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  13. 13.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  15. 15.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?
  16. 16.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?
  17. 17.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  19. 19.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  20. 20.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?
  21. 21.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?
  22. 22.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  23. 23.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  24. 24.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  25. 25.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  27. 27.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  29. 29.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  30. 30.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  31. 31.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?
  32. 32.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?
  33. 33.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  36. 36.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?
  37. 37.A leapfrog list starts 9, 7 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 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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.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?

Answer key

  1. 319
  2. 803
  3. 363
  4. 1199
  5. 572
  6. 308
  7. 253
  8. 143
  9. 517
  10. 814
  11. 946
  12. 825
  13. 484
  14. 198
  15. 418
  16. 627
  17. 561
  18. 1056
  19. 1199
  20. 1067
  21. 858
  22. 583
  23. 517
  24. 396
  25. 550
  26. 913
  27. 979
  28. 1001
  29. 1089
  30. 473
  31. 198
  32. 836
  33. 418
  34. 550
  35. 715
  36. 935
  37. 1111
  38. 396
  39. 891
  40. 759

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