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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 340 · 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 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  3. 3.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  4. 4.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  6. 6.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  9. 9.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?
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  12. 12.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  13. 13.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  14. 14.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  16. 16.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  17. 17.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?
  18. 18.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?
  19. 19.A leapfrog list starts 9, 1 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): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 6, 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): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  25. 25.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  27. 27.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  28. 28.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  29. 29.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  30. 30.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  32. 32.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?
  33. 33.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?
  34. 34.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  35. 35.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  36. 36.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?
  37. 37.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  38. 38.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  40. 40.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?

Answer key

  1. 374
  2. 1056
  3. 517
  4. 341
  5. 902
  6. 528
  7. 1144
  8. 407
  9. 594
  10. 748
  11. 286
  12. 550
  13. 429
  14. 1287
  15. 781
  16. 869
  17. 1023
  18. 451
  19. 583
  20. 1089
  21. 506
  22. 979
  23. 231
  24. 902
  25. 286
  26. 1034
  27. 946
  28. 781
  29. 1089
  30. 968
  31. 506
  32. 418
  33. 451
  34. 858
  35. 462
  36. 143
  37. 374
  38. 803
  39. 704
  40. 1067

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