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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 546 · 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 3, 5 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): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  3. 3.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?
  4. 4.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  6. 6.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  7. 7.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  8. 8.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?
  9. 9.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  10. 10.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  11. 11.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?
  12. 12.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  13. 13.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?
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  16. 16.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?
  17. 17.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  18. 18.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  23. 23.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  24. 24.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  25. 25.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  26. 26.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?
  27. 27.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  31. 31.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  36. 36.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  38. 38.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  40. 40.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 605
  2. 825
  3. 583
  4. 1232
  5. 671
  6. 847
  7. 649
  8. 1001
  9. 759
  10. 561
  11. 396
  12. 198
  13. 737
  14. 924
  15. 649
  16. 583
  17. 528
  18. 418
  19. 396
  20. 1122
  21. 770
  22. 968
  23. 671
  24. 473
  25. 1232
  26. 1111
  27. 484
  28. 341
  29. 462
  30. 231
  31. 704
  32. 737
  33. 495
  34. 495
  35. 1012
  36. 341
  37. 924
  38. 715
  39. 847
  40. 825

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