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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 74 · 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 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  3. 3.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  4. 4.A leapfrog list starts 9, 3 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): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  6. 6.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  8. 8.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?
  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. 10.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  11. 11.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  16. 16.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?
  17. 17.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  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. 19.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  20. 20.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  21. 21.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  23. 23.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?
  24. 24.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?
  25. 25.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  26. 26.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  28. 28.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  30. 30.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  31. 31.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?
  32. 32.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  33. 33.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  34. 34.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?
  35. 35.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?

Answer key

  1. 374
  2. 869
  3. 462
  4. 759
  5. 374
  6. 935
  7. 528
  8. 605
  9. 660
  10. 759
  11. 451
  12. 407
  13. 946
  14. 341
  15. 253
  16. 231
  17. 682
  18. 418
  19. 693
  20. 341
  21. 869
  22. 1012
  23. 737
  24. 638
  25. 902
  26. 968
  27. 704
  28. 781
  29. 814
  30. 836
  31. 462
  32. 550
  33. 198
  34. 1199
  35. 1287
  36. 847
  37. 1067
  38. 913
  39. 1144
  40. 1056

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