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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 433 · 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): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  2. 2.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?
  3. 3.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  4. 4.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  6. 6.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?
  7. 7.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?
  8. 8.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  16. 16.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  23. 23.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?
  24. 24.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  25. 25.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  28. 28.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  29. 29.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  30. 30.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  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.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  38. 38.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 913
  2. 286
  3. 748
  4. 594
  5. 770
  6. 880
  7. 286
  8. 682
  9. 484
  10. 308
  11. 583
  12. 792
  13. 594
  14. 506
  15. 924
  16. 715
  17. 781
  18. 869
  19. 572
  20. 550
  21. 902
  22. 396
  23. 418
  24. 704
  25. 517
  26. 803
  27. 649
  28. 506
  29. 616
  30. 253
  31. 198
  32. 462
  33. 418
  34. 143
  35. 495
  36. 341
  37. 231
  38. 550
  39. 946
  40. 836

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