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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 159 · 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 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  6. 6.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  7. 7.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?
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  10. 10.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  12. 12.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?
  13. 13.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  14. 14.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?
  15. 15.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  16. 16.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  17. 17.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  19. 19.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.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?
  21. 21.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?
  22. 22.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  23. 23.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?
  24. 24.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  25. 25.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?
  26. 26.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  27. 27.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?
  28. 28.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  30. 30.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  31. 31.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?
  32. 32.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  33. 33.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?
  34. 34.A leapfrog list starts 3, 9 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, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  37. 37.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  39. 39.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  40. 40.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =

Answer key

  1. 517
  2. 1001
  3. 1001
  4. 396
  5. 759
  6. 308
  7. 506
  8. 781
  9. 869
  10. 748
  11. 1199
  12. 473
  13. 825
  14. 847
  15. 550
  16. 253
  17. 308
  18. 671
  19. 605
  20. 1122
  21. 671
  22. 968
  23. 660
  24. 704
  25. 143
  26. 627
  27. 1177
  28. 891
  29. 814
  30. 363
  31. 946
  32. 902
  33. 803
  34. 957
  35. 253
  36. 1056
  37. 704
  38. 759
  39. 231
  40. 726

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