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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 701 · 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 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  4. 4.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  10. 10.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  11. 11.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?
  12. 12.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  13. 13.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  14. 14.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?
  15. 15.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  16. 16.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  17. 17.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  18. 18.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  19. 19.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  20. 20.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?
  21. 21.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  22. 22.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?
  23. 23.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  25. 25.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  26. 26.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  27. 27.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?
  28. 28.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  31. 31.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  32. 32.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  33. 33.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?
  34. 34.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  35. 35.A leapfrog list starts 7, 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 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.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?
  40. 40.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?

Answer key

  1. 1067
  2. 737
  3. 979
  4. 770
  5. 946
  6. 1199
  7. 341
  8. 814
  9. 594
  10. 1012
  11. 495
  12. 418
  13. 451
  14. 858
  15. 759
  16. 693
  17. 913
  18. 814
  19. 253
  20. 462
  21. 561
  22. 902
  23. 792
  24. 1111
  25. 143
  26. 495
  27. 396
  28. 1001
  29. 847
  30. 880
  31. 429
  32. 792
  33. 935
  34. 341
  35. 561
  36. 407
  37. 528
  38. 462
  39. 891
  40. 1012

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