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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 529 · 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. 1.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  3. 3.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  4. 4.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  5. 5.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  7. 7.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  9. 9.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  10. 10.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  12. 12.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  14. 14.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?
  15. 15.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  20. 20.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?
  21. 21.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  22. 22.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  23. 23.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?
  24. 24.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  25. 25.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?
  26. 26.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  32. 32.A leapfrog list starts 8, 2 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 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  39. 39.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  40. 40.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =

Answer key

  1. 869
  2. 429
  3. 759
  4. 341
  5. 737
  6. 671
  7. 660
  8. 660
  9. 561
  10. 781
  11. 814
  12. 1012
  13. 396
  14. 407
  15. 143
  16. 935
  17. 407
  18. 308
  19. 308
  20. 869
  21. 550
  22. 1287
  23. 671
  24. 737
  25. 143
  26. 671
  27. 825
  28. 143
  29. 1177
  30. 715
  31. 616
  32. 616
  33. 198
  34. 627
  35. 1199
  36. 759
  37. 792
  38. 979
  39. 429
  40. 1067

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