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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 847 · 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. 1.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  2. 2.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?
  3. 3.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  4. 4.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?
  5. 5.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  6. 6.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?
  7. 7.A leapfrog list starts 1, 9 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): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  13. 13.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?
  14. 14.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  23. 23.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?
  24. 24.A leapfrog list starts 1, 2 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 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  32. 32.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  33. 33.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  34. 34.A leapfrog list starts 4, 5 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): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  37. 37.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  38. 38.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 671
  2. 704
  3. 198
  4. 363
  5. 759
  6. 682
  7. 847
  8. 231
  9. 902
  10. 616
  11. 935
  12. 1034
  13. 847
  14. 616
  15. 396
  16. 407
  17. 462
  18. 1144
  19. 814
  20. 1122
  21. 396
  22. 726
  23. 1111
  24. 231
  25. 143
  26. 572
  27. 407
  28. 363
  29. 583
  30. 539
  31. 902
  32. 704
  33. 1199
  34. 660
  35. 418
  36. 374
  37. 792
  38. 462
  39. 957
  40. 143

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