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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 60 · 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. 1.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  2. 2.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?
  3. 3.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?
  4. 4.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  7. 7.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?
  8. 8.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  9. 9.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?
  10. 10.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 9, 5 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): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  14. 14.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  15. 15.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  18. 18.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  20. 20.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  22. 22.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  23. 23.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  25. 25.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  26. 26.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  27. 27.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?
  28. 28.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.A leapfrog list starts 1, 3 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 7, 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, 7 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 3, 5 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): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  34. 34.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  35. 35.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  37. 37.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?
  38. 38.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =

Answer key

  1. 1067
  2. 253
  3. 1177
  4. 1034
  5. 286
  6. 671
  7. 495
  8. 1111
  9. 759
  10. 781
  11. 737
  12. 935
  13. 1111
  14. 858
  15. 473
  16. 935
  17. 374
  18. 825
  19. 407
  20. 715
  21. 473
  22. 1023
  23. 231
  24. 902
  25. 913
  26. 407
  27. 737
  28. 550
  29. 319
  30. 913
  31. 891
  32. 605
  33. 1144
  34. 1034
  35. 649
  36. 418
  37. 550
  38. 594
  39. 572
  40. 759

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