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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 8 · 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 9, 8 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 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  5. 5.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  6. 6.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  7. 7.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  9. 9.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  10. 10.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  11. 11.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  12. 12.A leapfrog list starts 7, 1 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 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  22. 22.A leapfrog list starts 3, 1 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): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  24. 24.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  25. 25.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  26. 26.A leapfrog list starts 1, 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): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  28. 28.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?
  29. 29.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  30. 30.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  31. 31.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?
  32. 32.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?
  33. 33.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  34. 34.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  39. 39.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?
  40. 40.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =

Answer key

  1. 693
  2. 1199
  3. 308
  4. 517
  5. 506
  6. 770
  7. 495
  8. 583
  9. 528
  10. 462
  11. 891
  12. 473
  13. 1111
  14. 913
  15. 462
  16. 1199
  17. 638
  18. 319
  19. 737
  20. 968
  21. 847
  22. 253
  23. 539
  24. 1067
  25. 726
  26. 847
  27. 781
  28. 484
  29. 715
  30. 616
  31. 407
  32. 924
  33. 1111
  34. 561
  35. 957
  36. 957
  37. 891
  38. 1232
  39. 1056
  40. 968

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