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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 446 · 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): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  2. 2.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  4. 4.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.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?
  6. 6.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?
  7. 7.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  8. 8.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  9. 9.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  10. 10.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  11. 11.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?
  12. 12.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  13. 13.A leapfrog list starts 3, 2 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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  15. 15.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?
  16. 16.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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. 18.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  19. 19.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  20. 20.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?
  21. 21.A leapfrog list starts 2, 6 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): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  23. 23.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  24. 24.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  27. 27.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  28. 28.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  29. 29.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  30. 30.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?
  31. 31.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?
  32. 32.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  33. 33.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  34. 34.A leapfrog list starts 3, 6 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): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  36. 36.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  38. 38.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  39. 39.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  40. 40.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?

Answer key

  1. 572
  2. 627
  3. 1012
  4. 1056
  5. 462
  6. 407
  7. 286
  8. 1089
  9. 902
  10. 594
  11. 396
  12. 1012
  13. 341
  14. 594
  15. 1001
  16. 1089
  17. 143
  18. 759
  19. 1111
  20. 803
  21. 638
  22. 737
  23. 1287
  24. 671
  25. 858
  26. 1056
  27. 1001
  28. 847
  29. 572
  30. 517
  31. 935
  32. 814
  33. 396
  34. 693
  35. 627
  36. 660
  37. 528
  38. 924
  39. 429
  40. 407

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