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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 481 · 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): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  4. 4.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  5. 5.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?
  6. 6.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?
  7. 7.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  8. 8.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?
  9. 9.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  10. 10.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.A leapfrog list starts 3, 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 7, 7 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 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  15. 15.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  16. 16.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  18. 18.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?
  19. 19.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  20. 20.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  21. 21.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  22. 22.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?
  23. 23.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?
  24. 24.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  27. 27.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  28. 28.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?
  29. 29.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?
  30. 30.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  31. 31.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  35. 35.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  36. 36.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  37. 37.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?
  38. 38.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?

Answer key

  1. 396
  2. 1056
  3. 715
  4. 737
  5. 286
  6. 891
  7. 1001
  8. 825
  9. 539
  10. 759
  11. 693
  12. 1001
  13. 1144
  14. 319
  15. 902
  16. 1177
  17. 539
  18. 143
  19. 1089
  20. 341
  21. 1232
  22. 704
  23. 561
  24. 1023
  25. 979
  26. 286
  27. 253
  28. 572
  29. 627
  30. 704
  31. 462
  32. 660
  33. 550
  34. 605
  35. 418
  36. 506
  37. 231
  38. 803
  39. 1144
  40. 671

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