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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 523 · 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. 1.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  2. 2.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.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?
  7. 7.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  8. 8.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?
  9. 9.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?
  10. 10.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  11. 11.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?
  12. 12.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  13. 13.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  14. 14.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  15. 15.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?
  16. 16.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.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?
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  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 3, 8 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): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  23. 23.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?
  24. 24.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.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?
  26. 26.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  27. 27.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  29. 29.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.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?
  33. 33.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  35. 35.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  36. 36.A leapfrog list starts 4, 3 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. 38.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  39. 39.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  40. 40.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?

Answer key

  1. 495
  2. 484
  3. 286
  4. 407
  5. 418
  6. 847
  7. 231
  8. 594
  9. 517
  10. 319
  11. 869
  12. 583
  13. 374
  14. 198
  15. 858
  16. 616
  17. 770
  18. 363
  19. 660
  20. 803
  21. 869
  22. 605
  23. 924
  24. 979
  25. 1199
  26. 1012
  27. 1056
  28. 1122
  29. 671
  30. 396
  31. 1023
  32. 374
  33. 418
  34. 957
  35. 770
  36. 484
  37. 572
  38. 759
  39. 473
  40. 473

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