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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 532 · 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 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  3. 3.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  4. 4.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  5. 5.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  6. 6.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?
  7. 7.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?
  8. 8.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  9. 9.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  10. 10.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?
  11. 11.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  13. 13.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  16. 16.A leapfrog list starts 8, 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 4, 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 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  21. 21.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?
  22. 22.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  23. 23.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  25. 25.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  27. 27.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?
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  30. 30.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  31. 31.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  32. 32.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?
  33. 33.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  34. 34.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  35. 35.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.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?
  37. 37.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?
  38. 38.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?

Answer key

  1. 957
  2. 858
  3. 308
  4. 198
  5. 682
  6. 308
  7. 869
  8. 1012
  9. 880
  10. 1111
  11. 143
  12. 451
  13. 759
  14. 1111
  15. 748
  16. 1232
  17. 572
  18. 1144
  19. 550
  20. 484
  21. 143
  22. 957
  23. 1056
  24. 1034
  25. 396
  26. 671
  27. 374
  28. 550
  29. 1012
  30. 869
  31. 825
  32. 528
  33. 517
  34. 792
  35. 605
  36. 1177
  37. 1122
  38. 506
  39. 660
  40. 1287

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