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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 937 · 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): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  2. 2.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  4. 4.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.A leapfrog list starts 1, 8 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): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  7. 7.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?
  8. 8.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  9. 9.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  11. 11.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  12. 12.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?
  13. 13.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  14. 14.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  15. 15.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?
  16. 16.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  17. 17.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?
  18. 18.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  19. 19.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  20. 20.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  21. 21.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  23. 23.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?
  24. 24.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 3, 9 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): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  28. 28.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  30. 30.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  31. 31.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?
  32. 32.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?
  33. 33.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  34. 34.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?
  35. 35.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?
  36. 36.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  38. 38.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?
  39. 39.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  40. 40.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =

Answer key

  1. 682
  2. 605
  3. 759
  4. 1199
  5. 759
  6. 396
  7. 1023
  8. 847
  9. 880
  10. 704
  11. 814
  12. 847
  13. 550
  14. 583
  15. 737
  16. 429
  17. 704
  18. 473
  19. 957
  20. 1144
  21. 935
  22. 803
  23. 957
  24. 506
  25. 374
  26. 957
  27. 539
  28. 517
  29. 143
  30. 748
  31. 825
  32. 847
  33. 638
  34. 935
  35. 616
  36. 1199
  37. 484
  38. 946
  39. 572
  40. 1111

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