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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 267 · 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. 1.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  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.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  5. 5.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  6. 6.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  7. 7.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  11. 11.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?
  12. 12.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  13. 13.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?
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  16. 16.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  18. 18.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?
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 8, 5 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): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  23. 23.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  24. 24.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  25. 25.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  26. 26.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  27. 27.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  30. 30.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  31. 31.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?
  32. 32.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  37. 37.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  39. 39.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  40. 40.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 594
  2. 803
  3. 583
  4. 341
  5. 759
  6. 616
  7. 726
  8. 935
  9. 946
  10. 517
  11. 407
  12. 869
  13. 935
  14. 792
  15. 429
  16. 374
  17. 594
  18. 836
  19. 1122
  20. 1287
  21. 880
  22. 374
  23. 539
  24. 935
  25. 143
  26. 462
  27. 847
  28. 143
  29. 1034
  30. 682
  31. 451
  32. 561
  33. 1023
  34. 902
  35. 1001
  36. 583
  37. 1144
  38. 1056
  39. 418
  40. 1034

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