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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 873 · 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, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  4. 4.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  5. 5.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  6. 6.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?
  7. 7.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  8. 8.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  9. 9.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  17. 17.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  19. 19.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?
  20. 20.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  21. 21.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  22. 22.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  23. 23.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  24. 24.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  25. 25.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  26. 26.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?
  27. 27.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  28. 28.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  29. 29.A leapfrog list starts 7, 3 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 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  33. 33.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?
  34. 34.A leapfrog list starts 2, 6 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 7, 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 3, 6 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): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  38. 38.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  40. 40.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =

Answer key

  1. 429
  2. 143
  3. 1287
  4. 957
  5. 693
  6. 715
  7. 671
  8. 1122
  9. 1023
  10. 1034
  11. 517
  12. 671
  13. 814
  14. 506
  15. 814
  16. 726
  17. 638
  18. 847
  19. 462
  20. 913
  21. 902
  22. 979
  23. 550
  24. 473
  25. 715
  26. 671
  27. 891
  28. 1199
  29. 649
  30. 605
  31. 660
  32. 781
  33. 781
  34. 638
  35. 913
  36. 693
  37. 407
  38. 528
  39. 979
  40. 418

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