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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 367 · 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. 1.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  2. 2.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?
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  7. 7.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?
  8. 8.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?
  9. 9.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  10. 10.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.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?
  13. 13.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  16. 16.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.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?
  18. 18.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  19. 19.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?
  20. 20.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  26. 26.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  27. 27.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?
  28. 28.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  29. 29.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.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?
  31. 31.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  32. 32.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  34. 34.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?
  35. 35.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.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?
  37. 37.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?
  38. 38.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  40. 40.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =

Answer key

  1. 781
  2. 1232
  3. 825
  4. 968
  5. 550
  6. 363
  7. 1012
  8. 308
  9. 495
  10. 198
  11. 781
  12. 286
  13. 968
  14. 649
  15. 946
  16. 858
  17. 1001
  18. 814
  19. 451
  20. 770
  21. 1232
  22. 847
  23. 935
  24. 671
  25. 286
  26. 319
  27. 484
  28. 682
  29. 847
  30. 583
  31. 671
  32. 231
  33. 231
  34. 715
  35. 143
  36. 506
  37. 979
  38. 891
  39. 836
  40. 715

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