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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 725 · 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, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  3. 3.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?
  4. 4.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  5. 5.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  6. 6.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  7. 7.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  8. 8.A leapfrog list starts 1, 7 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 3, 1 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 7, 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. 12.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  13. 13.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?
  14. 14.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  15. 15.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  16. 16.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  19. 19.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  20. 20.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  21. 21.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  23. 23.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  26. 26.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?
  27. 27.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?
  28. 28.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.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?
  30. 30.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?
  31. 31.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.A leapfrog list starts 5, 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): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?

Answer key

  1. 781
  2. 693
  3. 869
  4. 715
  5. 473
  6. 1056
  7. 616
  8. 671
  9. 253
  10. 473
  11. 473
  12. 396
  13. 792
  14. 1067
  15. 913
  16. 792
  17. 825
  18. 198
  19. 1034
  20. 561
  21. 726
  22. 649
  23. 319
  24. 649
  25. 1144
  26. 506
  27. 253
  28. 583
  29. 1144
  30. 572
  31. 847
  32. 396
  33. 418
  34. 759
  35. 979
  36. 726
  37. 715
  38. 1177
  39. 715
  40. 671

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