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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 396 · 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 7, 8 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): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  3. 3.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?
  4. 4.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  5. 5.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  6. 6.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  13. 13.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  14. 14.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?
  15. 15.A leapfrog list starts 2, 9 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, 9 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): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  19. 19.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  20. 20.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?
  21. 21.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  22. 22.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  24. 24.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  25. 25.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?
  26. 26.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  28. 28.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  29. 29.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  33. 33.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?
  34. 34.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  39. 39.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?
  40. 40.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =

Answer key

  1. 1089
  2. 1023
  3. 1111
  4. 803
  5. 1177
  6. 902
  7. 418
  8. 847
  9. 715
  10. 726
  11. 572
  12. 253
  13. 539
  14. 231
  15. 902
  16. 1012
  17. 550
  18. 374
  19. 660
  20. 1177
  21. 374
  22. 198
  23. 1089
  24. 286
  25. 1122
  26. 286
  27. 528
  28. 671
  29. 198
  30. 803
  31. 451
  32. 792
  33. 1056
  34. 726
  35. 693
  36. 880
  37. 770
  38. 341
  39. 539
  40. 407

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