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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 366 · 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. 1.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  2. 2.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  4. 4.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  5. 5.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  6. 6.A leapfrog list starts 4, 8 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): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  8. 8.A leapfrog list starts 3, 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.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  12. 12.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  13. 13.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  15. 15.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?
  16. 16.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  17. 17.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  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.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?
  20. 20.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  21. 21.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  22. 22.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  23. 23.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  25. 25.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?
  26. 26.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  27. 27.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.A leapfrog list starts 4, 6 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  35. 35.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?
  36. 36.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  37. 37.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?
  38. 38.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  39. 39.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?

Answer key

  1. 341
  2. 583
  3. 759
  4. 858
  5. 726
  6. 924
  7. 638
  8. 517
  9. 660
  10. 770
  11. 957
  12. 682
  13. 286
  14. 1067
  15. 341
  16. 308
  17. 935
  18. 759
  19. 484
  20. 704
  21. 594
  22. 946
  23. 1111
  24. 418
  25. 803
  26. 660
  27. 858
  28. 693
  29. 583
  30. 957
  31. 253
  32. 671
  33. 748
  34. 1056
  35. 308
  36. 1012
  37. 946
  38. 528
  39. 770
  40. 319

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