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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 761 · 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, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  2. 2.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?
  3. 3.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  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.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?
  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.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?
  10. 10.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?
  11. 11.A leapfrog list starts 7, 3 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): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  13. 13.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.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?
  16. 16.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  18. 18.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  20. 20.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?
  21. 21.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  22. 22.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?
  23. 23.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  24. 24.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  29. 29.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  30. 30.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  31. 31.A leapfrog list starts 3, 3 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 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.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?
  35. 35.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  37. 37.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  38. 38.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  39. 39.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =

Answer key

  1. 517
  2. 143
  3. 1089
  4. 473
  5. 341
  6. 671
  7. 748
  8. 968
  9. 143
  10. 462
  11. 649
  12. 1111
  13. 1056
  14. 231
  15. 319
  16. 594
  17. 143
  18. 1287
  19. 759
  20. 781
  21. 253
  22. 759
  23. 1067
  24. 671
  25. 253
  26. 1034
  27. 825
  28. 847
  29. 407
  30. 418
  31. 429
  32. 759
  33. 924
  34. 583
  35. 594
  36. 715
  37. 561
  38. 693
  39. 462
  40. 847

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