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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 315 · 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, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  3. 3.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  4. 4.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  5. 5.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  7. 7.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  8. 8.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  9. 9.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?
  10. 10.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?
  11. 11.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  13. 13.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  14. 14.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?
  15. 15.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?
  16. 16.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  17. 17.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?
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  20. 20.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  23. 23.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  24. 24.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  25. 25.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  26. 26.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?
  27. 27.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  28. 28.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  29. 29.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?
  30. 30.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  32. 32.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?
  33. 33.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  35. 35.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  36. 36.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  37. 37.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?
  38. 38.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?
  39. 39.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  40. 40.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?

Answer key

  1. 825
  2. 671
  3. 253
  4. 286
  5. 506
  6. 847
  7. 363
  8. 737
  9. 374
  10. 1122
  11. 1287
  12. 792
  13. 583
  14. 770
  15. 418
  16. 143
  17. 143
  18. 594
  19. 847
  20. 924
  21. 891
  22. 792
  23. 693
  24. 605
  25. 517
  26. 836
  27. 594
  28. 660
  29. 451
  30. 682
  31. 396
  32. 341
  33. 495
  34. 253
  35. 407
  36. 924
  37. 858
  38. 748
  39. 561
  40. 1023

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