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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 929 · 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): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  2. 2.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  3. 3.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?
  4. 4.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?
  5. 5.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 5, 8 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 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.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?
  12. 12.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?
  13. 13.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?
  14. 14.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  15. 15.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  17. 17.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?
  18. 18.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  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, 7 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. 23.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  24. 24.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?
  25. 25.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?
  26. 26.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  27. 27.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  28. 28.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  29. 29.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?
  30. 30.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?
  31. 31.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  33. 33.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  35. 35.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?
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  38. 38.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?
  39. 39.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?

Answer key

  1. 1111
  2. 561
  3. 913
  4. 1034
  5. 1122
  6. 693
  7. 902
  8. 407
  9. 979
  10. 869
  11. 253
  12. 341
  13. 495
  14. 286
  15. 583
  16. 759
  17. 814
  18. 583
  19. 792
  20. 1122
  21. 946
  22. 198
  23. 374
  24. 693
  25. 847
  26. 660
  27. 781
  28. 231
  29. 1177
  30. 792
  31. 308
  32. 737
  33. 1111
  34. 396
  35. 517
  36. 858
  37. 308
  38. 231
  39. 715
  40. 671

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