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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 91 · 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): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  2. 2.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?
  3. 3.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  4. 4.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  6. 6.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?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  9. 9.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?
  10. 10.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  11. 11.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  12. 12.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  13. 13.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?
  14. 14.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  16. 16.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?
  17. 17.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?
  18. 18.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  19. 19.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  20. 20.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  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 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  30. 30.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?
  31. 31.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  32. 32.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  33. 33.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  34. 34.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  36. 36.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  37. 37.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  40. 40.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =

Answer key

  1. 341
  2. 1232
  3. 429
  4. 374
  5. 649
  6. 770
  7. 143
  8. 1056
  9. 1067
  10. 671
  11. 286
  12. 539
  13. 407
  14. 913
  15. 495
  16. 847
  17. 1001
  18. 759
  19. 924
  20. 869
  21. 396
  22. 462
  23. 671
  24. 583
  25. 902
  26. 528
  27. 671
  28. 902
  29. 198
  30. 143
  31. 682
  32. 407
  33. 1199
  34. 671
  35. 594
  36. 308
  37. 583
  38. 253
  39. 484
  40. 198

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