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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 699 · 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. 1.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  2. 2.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?
  3. 3.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?
  4. 4.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  6. 6.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  7. 7.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.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?
  10. 10.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  11. 11.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  13. 13.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?
  14. 14.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  15. 15.A leapfrog list starts 5, 6 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): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  17. 17.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  18. 18.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  20. 20.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  21. 21.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?
  22. 22.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  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): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  26. 26.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  28. 28.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?
  29. 29.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?
  30. 30.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  31. 31.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  33. 33.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?
  34. 34.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  35. 35.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  36. 36.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?
  37. 37.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?
  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. 39.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?

Answer key

  1. 484
  2. 198
  3. 1023
  4. 374
  5. 935
  6. 1232
  7. 1122
  8. 561
  9. 968
  10. 792
  11. 770
  12. 902
  13. 407
  14. 847
  15. 803
  16. 396
  17. 671
  18. 473
  19. 1034
  20. 253
  21. 924
  22. 869
  23. 363
  24. 1023
  25. 638
  26. 671
  27. 418
  28. 407
  29. 759
  30. 836
  31. 495
  32. 1001
  33. 451
  34. 539
  35. 1034
  36. 473
  37. 847
  38. 1232
  39. 1056
  40. 308

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