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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 706 · 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 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  3. 3.A leapfrog list starts 2, 5 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 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  6. 6.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  8. 8.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  10. 10.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  11. 11.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  12. 12.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?
  13. 13.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  15. 15.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  16. 16.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  19. 19.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  20. 20.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  21. 21.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?
  22. 22.A leapfrog list starts 2, 6 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 1, 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 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  37. 37.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  38. 38.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  39. 39.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  40. 40.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =

Answer key

  1. 539
  2. 704
  3. 550
  4. 957
  5. 143
  6. 847
  7. 407
  8. 946
  9. 429
  10. 1023
  11. 286
  12. 814
  13. 198
  14. 550
  15. 913
  16. 660
  17. 561
  18. 286
  19. 539
  20. 418
  21. 671
  22. 638
  23. 143
  24. 1287
  25. 1111
  26. 792
  27. 1067
  28. 891
  29. 605
  30. 671
  31. 671
  32. 561
  33. 715
  34. 473
  35. 484
  36. 902
  37. 616
  38. 737
  39. 1144
  40. 231

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