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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 724 · 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 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  4. 4.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  5. 5.A leapfrog list starts 6, 2 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): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  11. 11.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?
  12. 12.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?
  13. 13.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  15. 15.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  16. 16.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  17. 17.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.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?
  19. 19.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  22. 22.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  23. 23.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  28. 28.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  29. 29.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  30. 30.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  31. 31.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  32. 32.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?
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  35. 35.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  36. 36.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?

Answer key

  1. 638
  2. 704
  3. 253
  4. 671
  5. 506
  6. 979
  7. 693
  8. 495
  9. 363
  10. 891
  11. 1023
  12. 319
  13. 649
  14. 935
  15. 517
  16. 484
  17. 484
  18. 1001
  19. 1177
  20. 979
  21. 1056
  22. 902
  23. 671
  24. 143
  25. 506
  26. 451
  27. 1199
  28. 748
  29. 847
  30. 671
  31. 814
  32. 726
  33. 572
  34. 781
  35. 550
  36. 539
  37. 407
  38. 396
  39. 473
  40. 561

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