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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 913 · 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): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  2. 2.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  3. 3.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?
  4. 4.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?
  5. 5.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  6. 6.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?
  7. 7.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  8. 8.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  15. 15.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  16. 16.A leapfrog list starts 3, 2 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, 1 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): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  19. 19.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?
  20. 20.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  23. 23.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  25. 25.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  27. 27.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?
  28. 28.A leapfrog list starts 7, 7 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): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  30. 30.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  31. 31.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  32. 32.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.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?
  35. 35.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  36. 36.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?
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  39. 39.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  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. 1067
  2. 671
  3. 550
  4. 1177
  5. 1122
  6. 638
  7. 627
  8. 506
  9. 660
  10. 407
  11. 308
  12. 770
  13. 704
  14. 484
  15. 363
  16. 341
  17. 308
  18. 913
  19. 748
  20. 1089
  21. 231
  22. 583
  23. 847
  24. 968
  25. 462
  26. 572
  27. 495
  28. 1001
  29. 506
  30. 1012
  31. 341
  32. 968
  33. 726
  34. 462
  35. 418
  36. 924
  37. 374
  38. 1001
  39. 429
  40. 671

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