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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 750 · 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 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  3. 3.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  4. 4.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  6. 6.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?
  7. 7.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  8. 8.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  9. 9.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?
  10. 10.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  15. 15.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  16. 16.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  23. 23.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  25. 25.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  26. 26.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  28. 28.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  29. 29.A leapfrog list starts 3, 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. 31.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  32. 32.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?
  33. 33.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  34. 34.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  35. 35.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  37. 37.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?
  38. 38.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 308
  2. 880
  3. 671
  4. 286
  5. 198
  6. 495
  7. 528
  8. 396
  9. 638
  10. 759
  11. 759
  12. 638
  13. 1122
  14. 803
  15. 891
  16. 1177
  17. 1023
  18. 1067
  19. 231
  20. 286
  21. 561
  22. 759
  23. 858
  24. 693
  25. 924
  26. 979
  27. 726
  28. 671
  29. 517
  30. 231
  31. 979
  32. 1111
  33. 847
  34. 308
  35. 704
  36. 693
  37. 1001
  38. 1199
  39. 880
  40. 198

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