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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 685 · 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. 1.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  2. 2.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  5. 5.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  6. 6.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  7. 7.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?
  8. 8.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  13. 13.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.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?
  16. 16.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  17. 17.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?
  18. 18.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?
  19. 19.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  20. 20.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  21. 21.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  23. 23.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?
  24. 24.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  26. 26.A leapfrog list starts 5, 1 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): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  28. 28.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  34. 34.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  36. 36.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  37. 37.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?
  38. 38.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  40. 40.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 198
  2. 770
  3. 1287
  4. 638
  5. 913
  6. 869
  7. 1023
  8. 1177
  9. 891
  10. 517
  11. 781
  12. 418
  13. 407
  14. 341
  15. 770
  16. 473
  17. 869
  18. 572
  19. 308
  20. 682
  21. 649
  22. 715
  23. 759
  24. 704
  25. 649
  26. 363
  27. 506
  28. 407
  29. 1232
  30. 671
  31. 737
  32. 792
  33. 891
  34. 506
  35. 748
  36. 528
  37. 429
  38. 1034
  39. 363
  40. 429

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