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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 296 · 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): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  2. 2.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  4. 4.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  5. 5.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  6. 6.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  7. 7.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  8. 8.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?
  9. 9.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  10. 10.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  11. 11.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?
  12. 12.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  13. 13.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  18. 18.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  20. 20.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  23. 23.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  24. 24.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?
  25. 25.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  26. 26.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  27. 27.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  28. 28.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  30. 30.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?
  31. 31.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?
  32. 32.A leapfrog list starts 5, 4 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): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  34. 34.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.A leapfrog list starts 1, 5 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, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  38. 38.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?

Answer key

  1. 847
  2. 759
  3. 660
  4. 407
  5. 1001
  6. 143
  7. 1111
  8. 869
  9. 880
  10. 858
  11. 792
  12. 715
  13. 847
  14. 759
  15. 836
  16. 825
  17. 869
  18. 836
  19. 770
  20. 1067
  21. 319
  22. 363
  23. 616
  24. 979
  25. 473
  26. 506
  27. 671
  28. 418
  29. 847
  30. 231
  31. 473
  32. 627
  33. 198
  34. 451
  35. 341
  36. 495
  37. 396
  38. 781
  39. 682
  40. 726

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