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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 741 · 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, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.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?
  4. 4.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  5. 5.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  6. 6.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?
  7. 7.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  8. 8.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  9. 9.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  11. 11.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?
  12. 12.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  13. 13.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?
  14. 14.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  15. 15.A leapfrog list starts 5, 3 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 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.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?
  18. 18.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  19. 19.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  20. 20.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  21. 21.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  22. 22.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?
  23. 23.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?
  24. 24.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  26. 26.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  27. 27.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  28. 28.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?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  31. 31.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?
  32. 32.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  37. 37.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 902
  2. 1232
  3. 847
  4. 715
  5. 1232
  6. 847
  7. 671
  8. 539
  9. 924
  10. 462
  11. 374
  12. 1012
  13. 528
  14. 781
  15. 539
  16. 561
  17. 660
  18. 429
  19. 1177
  20. 143
  21. 693
  22. 517
  23. 429
  24. 407
  25. 572
  26. 946
  27. 341
  28. 1001
  29. 374
  30. 924
  31. 495
  32. 902
  33. 517
  34. 198
  35. 1287
  36. 198
  37. 418
  38. 847
  39. 407
  40. 605

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