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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 858 · 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. 1.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  2. 2.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  4. 4.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  6. 6.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  7. 7.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?
  8. 8.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?
  9. 9.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  14. 14.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?
  15. 15.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?
  16. 16.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  18. 18.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  19. 19.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  27. 27.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  28. 28.A leapfrog list starts 8, 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): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  30. 30.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?
  31. 31.A leapfrog list starts 5, 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. 33.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?

Answer key

  1. 704
  2. 583
  3. 1232
  4. 143
  5. 847
  6. 902
  7. 825
  8. 770
  9. 902
  10. 693
  11. 825
  12. 1089
  13. 363
  14. 979
  15. 957
  16. 418
  17. 649
  18. 737
  19. 803
  20. 748
  21. 1012
  22. 396
  23. 902
  24. 792
  25. 495
  26. 528
  27. 561
  28. 1056
  29. 572
  30. 583
  31. 1067
  32. 616
  33. 671
  34. 528
  35. 726
  36. 495
  37. 671
  38. 1199
  39. 759
  40. 1122

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