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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 677 · 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. 1.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  2. 2.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  3. 3.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?
  4. 4.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  5. 5.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?
  6. 6.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?
  7. 7.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  8. 8.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?
  9. 9.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  11. 11.A leapfrog list starts 1, 6 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): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  13. 13.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  15. 15.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?
  16. 16.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  21. 21.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?
  22. 22.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  25. 25.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  27. 27.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  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, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  30. 30.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?
  31. 31.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  32. 32.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?
  33. 33.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  35. 35.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  36. 36.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?
  37. 37.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  38. 38.A leapfrog list starts 9, 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 6, 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 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 319
  2. 363
  3. 561
  4. 616
  5. 308
  6. 935
  7. 583
  8. 638
  9. 726
  10. 528
  11. 583
  12. 473
  13. 1034
  14. 869
  15. 407
  16. 583
  17. 308
  18. 902
  19. 924
  20. 836
  21. 396
  22. 308
  23. 462
  24. 1023
  25. 792
  26. 693
  27. 506
  28. 517
  29. 759
  30. 561
  31. 495
  32. 671
  33. 1067
  34. 429
  35. 627
  36. 913
  37. 902
  38. 583
  39. 682
  40. 814

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