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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 704 · 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 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  5. 5.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?
  6. 6.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?
  7. 7.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  8. 8.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?
  9. 9.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?
  10. 10.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  11. 11.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  12. 12.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  14. 14.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  15. 15.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?
  16. 16.A leapfrog list starts 4, 4 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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  19. 19.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?
  20. 20.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?
  21. 21.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  22. 22.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?
  23. 23.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  24. 24.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  28. 28.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  29. 29.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  31. 31.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?
  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. 33.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  34. 34.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  35. 35.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  38. 38.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?
  39. 39.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?

Answer key

  1. 583
  2. 407
  3. 957
  4. 924
  5. 847
  6. 1287
  7. 341
  8. 396
  9. 341
  10. 957
  11. 814
  12. 759
  13. 286
  14. 858
  15. 517
  16. 572
  17. 550
  18. 616
  19. 968
  20. 451
  21. 616
  22. 770
  23. 517
  24. 1067
  25. 495
  26. 847
  27. 231
  28. 407
  29. 671
  30. 396
  31. 528
  32. 473
  33. 671
  34. 473
  35. 363
  36. 1287
  37. 198
  38. 891
  39. 913
  40. 902

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