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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 551 · 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. 1.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  2. 2.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?
  3. 3.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  4. 4.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?
  5. 5.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?
  6. 6.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?
  7. 7.A leapfrog list starts 7, 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): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  9. 9.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  10. 10.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?
  11. 11.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  12. 12.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?
  13. 13.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  16. 16.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  17. 17.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  18. 18.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  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. 20.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  21. 21.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?
  22. 22.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  23. 23.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?
  24. 24.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?
  25. 25.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.A leapfrog list starts 4, 3 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 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  34. 34.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?
  35. 35.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  36. 36.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?
  37. 37.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 473
  2. 495
  3. 1001
  4. 1001
  5. 902
  6. 506
  7. 473
  8. 1177
  9. 319
  10. 462
  11. 143
  12. 1199
  13. 1122
  14. 902
  15. 341
  16. 825
  17. 759
  18. 528
  19. 682
  20. 638
  21. 627
  22. 561
  23. 572
  24. 583
  25. 726
  26. 605
  27. 1001
  28. 957
  29. 825
  30. 704
  31. 484
  32. 286
  33. 847
  34. 825
  35. 671
  36. 814
  37. 660
  38. 374
  39. 671
  40. 869

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