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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 280 · 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.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?
  2. 2.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  3. 3.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?
  4. 4.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  5. 5.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  7. 7.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?
  8. 8.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  15. 15.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  16. 16.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?
  17. 17.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  18. 18.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  29. 29.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  30. 30.A leapfrog list starts 7, 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 2, 8 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 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  35. 35.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?
  36. 36.A leapfrog list starts 8, 3 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.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  40. 40.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 583
  2. 968
  3. 649
  4. 836
  5. 781
  6. 759
  7. 1287
  8. 1232
  9. 561
  10. 803
  11. 1012
  12. 517
  13. 847
  14. 572
  15. 935
  16. 583
  17. 198
  18. 407
  19. 682
  20. 407
  21. 803
  22. 616
  23. 253
  24. 759
  25. 869
  26. 715
  27. 605
  28. 583
  29. 473
  30. 737
  31. 814
  32. 671
  33. 957
  34. 495
  35. 770
  36. 704
  37. 517
  38. 539
  39. 671
  40. 451

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