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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 68 · 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 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  3. 3.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  4. 4.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?
  5. 5.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  6. 6.A leapfrog list starts 3, 1 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): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  8. 8.A leapfrog list starts 5, 5 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 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  12. 12.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  13. 13.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  14. 14.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  15. 15.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  16. 16.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?
  17. 17.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  18. 18.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  19. 19.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  20. 20.A leapfrog list starts 1, 6 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 9, 7 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): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  23. 23.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  25. 25.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  26. 26.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?
  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.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?
  29. 29.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  31. 31.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?
  32. 32.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  33. 33.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?
  34. 34.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?
  35. 35.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  36. 36.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 1287
  2. 396
  3. 979
  4. 451
  5. 561
  6. 253
  7. 1001
  8. 715
  9. 770
  10. 462
  11. 1122
  12. 308
  13. 792
  14. 935
  15. 341
  16. 418
  17. 1089
  18. 814
  19. 737
  20. 583
  21. 1111
  22. 847
  23. 649
  24. 682
  25. 528
  26. 781
  27. 506
  28. 374
  29. 506
  30. 968
  31. 880
  32. 803
  33. 143
  34. 792
  35. 462
  36. 561
  37. 572
  38. 429
  39. 1287
  40. 396

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