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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 581 · 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. 1.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  2. 2.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?
  3. 3.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?
  4. 4.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  5. 5.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 8, 4 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): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  12. 12.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  14. 14.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?
  15. 15.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  16. 16.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  17. 17.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  18. 18.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?
  19. 19.A leapfrog list starts 4, 4 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 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  23. 23.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  25. 25.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  28. 28.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?
  29. 29.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.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?
  31. 31.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  34. 34.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?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  37. 37.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  38. 38.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  40. 40.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?

Answer key

  1. 671
  2. 693
  3. 649
  4. 231
  5. 858
  6. 1067
  7. 517
  8. 814
  9. 539
  10. 792
  11. 979
  12. 858
  13. 792
  14. 671
  15. 660
  16. 759
  17. 649
  18. 913
  19. 572
  20. 1122
  21. 1034
  22. 198
  23. 1089
  24. 1177
  25. 429
  26. 473
  27. 561
  28. 1056
  29. 319
  30. 1023
  31. 726
  32. 781
  33. 1232
  34. 1287
  35. 143
  36. 528
  37. 935
  38. 407
  39. 627
  40. 594

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