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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 509 · 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): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  2. 2.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?
  3. 3.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  4. 4.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?
  5. 5.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?
  6. 6.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 8, 6 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): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  11. 11.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  12. 12.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  13. 13.A leapfrog list starts 6, 8 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): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  15. 15.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?
  16. 16.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  17. 17.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?
  18. 18.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  19. 19.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  22. 22.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  24. 24.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  26. 26.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.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?
  28. 28.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  29. 29.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.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?
  31. 31.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  33. 33.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?
  34. 34.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  35. 35.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?
  36. 36.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?
  37. 37.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  39. 39.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  40. 40.A leapfrog list starts 1, 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. 858
  2. 418
  3. 286
  4. 594
  5. 671
  6. 847
  7. 506
  8. 946
  9. 968
  10. 715
  11. 660
  12. 1232
  13. 1034
  14. 528
  15. 693
  16. 583
  17. 506
  18. 495
  19. 814
  20. 935
  21. 979
  22. 539
  23. 858
  24. 858
  25. 528
  26. 308
  27. 517
  28. 1001
  29. 847
  30. 869
  31. 759
  32. 473
  33. 638
  34. 704
  35. 671
  36. 286
  37. 682
  38. 583
  39. 1199
  40. 319

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