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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 146 · 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): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  2. 2.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  3. 3.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  5. 5.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?
  6. 6.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.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?
  8. 8.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  9. 9.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.A leapfrog list starts 8, 1 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 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.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?
  14. 14.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  15. 15.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  17. 17.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?
  18. 18.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  21. 21.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?
  22. 22.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  23. 23.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  24. 24.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  26. 26.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  27. 27.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?
  28. 28.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?
  29. 29.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  30. 30.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  32. 32.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?
  33. 33.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  34. 34.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  35. 35.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  36. 36.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  38. 38.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  39. 39.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  40. 40.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?

Answer key

  1. 847
  2. 253
  3. 418
  4. 1287
  5. 781
  6. 418
  7. 253
  8. 286
  9. 924
  10. 506
  11. 528
  12. 506
  13. 825
  14. 781
  15. 671
  16. 407
  17. 308
  18. 231
  19. 649
  20. 902
  21. 759
  22. 803
  23. 660
  24. 231
  25. 924
  26. 561
  27. 550
  28. 759
  29. 396
  30. 396
  31. 968
  32. 825
  33. 814
  34. 979
  35. 1287
  36. 847
  37. 198
  38. 759
  39. 1012
  40. 550

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