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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 5 · 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): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  8. 8.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  9. 9.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?
  10. 10.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  12. 12.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?
  13. 13.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  16. 16.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  18. 18.A leapfrog list starts 7, 3 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 2, 3 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, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  21. 21.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  22. 22.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  24. 24.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  25. 25.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?
  26. 26.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  27. 27.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  29. 29.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  30. 30.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?
  31. 31.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  33. 33.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  34. 34.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?
  35. 35.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  36. 36.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  38. 38.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?
  39. 39.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  40. 40.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =

Answer key

  1. 693
  2. 1001
  3. 869
  4. 572
  5. 847
  6. 968
  7. 902
  8. 451
  9. 517
  10. 396
  11. 847
  12. 1144
  13. 1023
  14. 847
  15. 1067
  16. 286
  17. 1023
  18. 649
  19. 374
  20. 770
  21. 1001
  22. 1144
  23. 550
  24. 253
  25. 726
  26. 814
  27. 748
  28. 957
  29. 1232
  30. 451
  31. 473
  32. 803
  33. 407
  34. 891
  35. 1111
  36. 682
  37. 319
  38. 583
  39. 484
  40. 649

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