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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 338 · 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): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  2. 2.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  3. 3.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  6. 6.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  14. 14.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  15. 15.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  16. 16.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?
  17. 17.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  18. 18.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  20. 20.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  21. 21.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  22. 22.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  25. 25.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?
  26. 26.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  27. 27.A leapfrog list starts 4, 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 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  30. 30.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  31. 31.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  32. 32.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  33. 33.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?
  34. 34.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?
  35. 35.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  37. 37.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  38. 38.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?
  39. 39.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?

Answer key

  1. 869
  2. 451
  3. 682
  4. 957
  5. 605
  6. 704
  7. 825
  8. 396
  9. 1056
  10. 517
  11. 803
  12. 649
  13. 253
  14. 143
  15. 1023
  16. 143
  17. 1287
  18. 814
  19. 418
  20. 253
  21. 638
  22. 1287
  23. 572
  24. 517
  25. 517
  26. 198
  27. 1012
  28. 286
  29. 693
  30. 825
  31. 715
  32. 363
  33. 231
  34. 550
  35. 1232
  36. 341
  37. 693
  38. 605
  39. 737
  40. 836

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