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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 213 · 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. 1.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  2. 2.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  3. 3.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?
  4. 4.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  5. 5.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  13. 13.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?
  14. 14.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  15. 15.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  17. 17.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  19. 19.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?
  20. 20.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?
  21. 21.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  23. 23.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  24. 24.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  26. 26.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?
  27. 27.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  31. 31.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  32. 32.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  34. 34.A leapfrog list starts 7, 3 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): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  36. 36.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?
  37. 37.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?
  38. 38.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?

Answer key

  1. 979
  2. 1287
  3. 902
  4. 792
  5. 913
  6. 891
  7. 1287
  8. 759
  9. 1122
  10. 891
  11. 638
  12. 319
  13. 605
  14. 770
  15. 946
  16. 143
  17. 451
  18. 308
  19. 583
  20. 506
  21. 1056
  22. 374
  23. 418
  24. 341
  25. 748
  26. 770
  27. 1177
  28. 693
  29. 638
  30. 1111
  31. 671
  32. 550
  33. 693
  34. 649
  35. 693
  36. 847
  37. 418
  38. 143
  39. 759
  40. 704

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