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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 357 · 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): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  2. 2.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  3. 3.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  4. 4.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.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?
  6. 6.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  7. 7.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  8. 8.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?
  9. 9.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?
  10. 10.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  12. 12.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  13. 13.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  14. 14.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?
  15. 15.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?
  16. 16.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  18. 18.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?
  19. 19.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  20. 20.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?
  21. 21.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  26. 26.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  27. 27.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?
  28. 28.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  29. 29.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  30. 30.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?
  31. 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  32. 32.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?
  33. 33.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  35. 35.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?
  36. 36.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  37. 37.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  38. 38.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.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?
  40. 40.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =

Answer key

  1. 286
  2. 902
  3. 572
  4. 583
  5. 1023
  6. 308
  7. 484
  8. 748
  9. 880
  10. 1232
  11. 1122
  12. 1067
  13. 759
  14. 143
  15. 363
  16. 803
  17. 660
  18. 847
  19. 396
  20. 561
  21. 462
  22. 946
  23. 715
  24. 374
  25. 539
  26. 1177
  27. 847
  28. 517
  29. 847
  30. 649
  31. 616
  32. 902
  33. 495
  34. 594
  35. 495
  36. 627
  37. 693
  38. 473
  39. 462
  40. 1056

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