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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 299 · 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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  2. 2.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  3. 3.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  5. 5.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  6. 6.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  12. 12.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?
  13. 13.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  16. 16.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  17. 17.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  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. 21.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  22. 22.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?
  23. 23.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  24. 24.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?
  25. 25.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  26. 26.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  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. 28.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  29. 29.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?
  30. 30.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  31. 31.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  35. 35.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  38. 38.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  40. 40.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =

Answer key

  1. 143
  2. 935
  3. 462
  4. 1199
  5. 847
  6. 198
  7. 770
  8. 627
  9. 660
  10. 528
  11. 473
  12. 616
  13. 1056
  14. 418
  15. 1144
  16. 561
  17. 913
  18. 913
  19. 726
  20. 869
  21. 781
  22. 649
  23. 671
  24. 473
  25. 1067
  26. 495
  27. 1067
  28. 605
  29. 517
  30. 957
  31. 583
  32. 759
  33. 231
  34. 594
  35. 836
  36. 737
  37. 506
  38. 1012
  39. 770
  40. 704

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