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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 802 · 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. 1.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  2. 2.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?
  3. 3.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?
  4. 4.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  9. 9.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?
  10. 10.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  11. 11.A leapfrog list starts 1, 6 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 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  16. 16.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  21. 21.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?
  22. 22.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  23. 23.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.A leapfrog list starts 1, 8 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): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  30. 30.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?
  31. 31.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  32. 32.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?
  33. 33.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  34. 34.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  35. 35.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?
  36. 36.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  37. 37.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  38. 38.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?
  39. 39.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  40. 40.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =

Answer key

  1. 198
  2. 759
  3. 198
  4. 506
  5. 814
  6. 583
  7. 198
  8. 583
  9. 814
  10. 396
  11. 583
  12. 715
  13. 1199
  14. 495
  15. 1067
  16. 1001
  17. 825
  18. 319
  19. 583
  20. 451
  21. 671
  22. 1012
  23. 253
  24. 253
  25. 946
  26. 759
  27. 1122
  28. 759
  29. 869
  30. 902
  31. 935
  32. 143
  33. 847
  34. 539
  35. 1111
  36. 704
  37. 1177
  38. 836
  39. 1001
  40. 1199

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