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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 911 · 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. 1.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  2. 2.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  5. 5.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  6. 6.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?
  7. 7.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  8. 8.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  9. 9.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  10. 10.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?
  11. 11.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  13. 13.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  14. 14.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  15. 15.A leapfrog list starts 3, 7 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 8, 7 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.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  20. 20.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  22. 22.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  23. 23.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?
  24. 24.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?
  25. 25.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  26. 26.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  28. 28.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  30. 30.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  31. 31.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  32. 32.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  34. 34.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  35. 35.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  36. 36.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =

Answer key

  1. 704
  2. 649
  3. 550
  4. 858
  5. 902
  6. 528
  7. 143
  8. 429
  9. 770
  10. 231
  11. 253
  12. 473
  13. 1232
  14. 627
  15. 781
  16. 1056
  17. 550
  18. 374
  19. 374
  20. 429
  21. 418
  22. 748
  23. 814
  24. 396
  25. 407
  26. 286
  27. 715
  28. 506
  29. 913
  30. 847
  31. 693
  32. 979
  33. 968
  34. 396
  35. 880
  36. 319
  37. 473
  38. 1122
  39. 1144
  40. 231

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