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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 612 · 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): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  2. 2.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  3. 3.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  4. 4.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  5. 5.A leapfrog list starts 8, 8 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 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  8. 8.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?
  9. 9.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?
  10. 10.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?
  11. 11.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  12. 12.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  17. 17.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?
  18. 18.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  19. 19.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  20. 20.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?
  21. 21.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?
  22. 22.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  23. 23.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  24. 24.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?
  25. 25.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  26. 26.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?
  27. 27.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  28. 28.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?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  31. 31.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?
  32. 32.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  33. 33.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?
  34. 34.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?
  35. 35.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  36. 36.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  37. 37.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  39. 39.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =

Answer key

  1. 253
  2. 781
  3. 638
  4. 506
  5. 1144
  6. 1232
  7. 880
  8. 902
  9. 506
  10. 1001
  11. 759
  12. 616
  13. 462
  14. 638
  15. 506
  16. 726
  17. 462
  18. 847
  19. 363
  20. 671
  21. 407
  22. 528
  23. 1144
  24. 407
  25. 407
  26. 308
  27. 1023
  28. 814
  29. 627
  30. 198
  31. 759
  32. 495
  33. 1199
  34. 594
  35. 847
  36. 429
  37. 319
  38. 660
  39. 1111
  40. 627

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