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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 875 · 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, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  3. 3.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  4. 4.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?
  5. 5.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  7. 7.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?
  8. 8.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?
  9. 9.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?
  10. 10.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  11. 11.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  13. 13.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  15. 15.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?
  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.A leapfrog list starts 1, 5 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 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  20. 20.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?
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  26. 26.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  27. 27.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?
  28. 28.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?
  29. 29.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  30. 30.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?
  31. 31.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?
  32. 32.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  34. 34.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?
  35. 35.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  36. 36.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?
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  39. 39.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?
  40. 40.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 660
  2. 638
  3. 803
  4. 1023
  5. 682
  6. 462
  7. 528
  8. 726
  9. 374
  10. 627
  11. 803
  12. 374
  13. 550
  14. 792
  15. 605
  16. 231
  17. 495
  18. 759
  19. 1012
  20. 814
  21. 1199
  22. 847
  23. 979
  24. 341
  25. 143
  26. 308
  27. 671
  28. 803
  29. 550
  30. 407
  31. 957
  32. 616
  33. 1089
  34. 737
  35. 737
  36. 979
  37. 517
  38. 308
  39. 946
  40. 902

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