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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 956 · 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, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  5. 5.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.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?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  11. 11.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.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?
  13. 13.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  14. 14.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?
  15. 15.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  17. 17.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  18. 18.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  19. 19.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  21. 21.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  22. 22.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.A leapfrog list starts 3, 3 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 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.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?
  30. 30.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  31. 31.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  32. 32.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?
  33. 33.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  34. 34.A leapfrog list starts 6, 4 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): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  36. 36.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?
  37. 37.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  38. 38.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?
  39. 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  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. 682
  2. 803
  3. 407
  4. 847
  5. 473
  6. 671
  7. 572
  8. 1177
  9. 946
  10. 825
  11. 1012
  12. 1199
  13. 803
  14. 671
  15. 968
  16. 1232
  17. 814
  18. 462
  19. 605
  20. 143
  21. 1287
  22. 231
  23. 858
  24. 1111
  25. 770
  26. 429
  27. 825
  28. 605
  29. 462
  30. 671
  31. 363
  32. 770
  33. 429
  34. 682
  35. 847
  36. 946
  37. 913
  38. 517
  39. 616
  40. 902

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