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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 333 · 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.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.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?
  4. 4.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  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. 6.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  9. 9.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  10. 10.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?
  11. 11.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  12. 12.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  13. 13.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  14. 14.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?
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  18. 18.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  19. 19.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?
  20. 20.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  21. 21.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  22. 22.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?
  23. 23.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  24. 24.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.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?
  28. 28.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?
  29. 29.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  30. 30.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  31. 31.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?
  32. 32.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?
  33. 33.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =

Answer key

  1. 1144
  2. 1023
  3. 869
  4. 1232
  5. 814
  6. 341
  7. 737
  8. 638
  9. 429
  10. 231
  11. 1089
  12. 935
  13. 451
  14. 473
  15. 847
  16. 572
  17. 1144
  18. 517
  19. 495
  20. 462
  21. 1111
  22. 946
  23. 957
  24. 583
  25. 891
  26. 803
  27. 682
  28. 1034
  29. 1144
  30. 682
  31. 528
  32. 341
  33. 891
  34. 308
  35. 231
  36. 715
  37. 253
  38. 1111
  39. 506
  40. 671

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