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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 690 · 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.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  4. 4.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  5. 5.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?
  6. 6.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?
  7. 7.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  8. 8.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?
  9. 9.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  11. 11.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  14. 14.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?
  15. 15.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?
  16. 16.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  17. 17.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  23. 23.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?
  24. 24.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  26. 26.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?
  27. 27.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  28. 28.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  29. 29.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?
  30. 30.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  31. 31.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?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  34. 34.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 913
  2. 902
  3. 748
  4. 737
  5. 1199
  6. 671
  7. 572
  8. 968
  9. 605
  10. 583
  11. 495
  12. 792
  13. 1067
  14. 143
  15. 231
  16. 429
  17. 517
  18. 748
  19. 253
  20. 1199
  21. 407
  22. 583
  23. 1001
  24. 1034
  25. 319
  26. 374
  27. 561
  28. 506
  29. 418
  30. 781
  31. 759
  32. 638
  33. 1177
  34. 660
  35. 396
  36. 671
  37. 561
  38. 143
  39. 627
  40. 473

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