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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 934 · 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, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  2. 2.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  7. 7.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  8. 8.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  10. 10.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  17. 17.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  18. 18.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  20. 20.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  21. 21.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  24. 24.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  25. 25.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  26. 26.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  27. 27.A leapfrog list starts 8, 6 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 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  30. 30.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?
  31. 31.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  32. 32.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  33. 33.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?
  34. 34.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  35. 35.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  36. 36.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  37. 37.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  38. 38.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?
  39. 39.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?

Answer key

  1. 198
  2. 308
  3. 649
  4. 1012
  5. 341
  6. 880
  7. 935
  8. 836
  9. 539
  10. 869
  11. 143
  12. 484
  13. 1144
  14. 1023
  15. 682
  16. 759
  17. 847
  18. 198
  19. 1034
  20. 671
  21. 451
  22. 1122
  23. 682
  24. 484
  25. 858
  26. 660
  27. 968
  28. 660
  29. 506
  30. 638
  31. 583
  32. 550
  33. 473
  34. 803
  35. 968
  36. 726
  37. 143
  38. 1056
  39. 759
  40. 781

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