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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 416 · 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. 1.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  2. 2.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?
  3. 3.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?
  4. 4.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  5. 5.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?
  6. 6.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?
  7. 7.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  8. 8.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  9. 9.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  11. 11.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  13. 13.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  14. 14.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?
  15. 15.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  20. 20.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  21. 21.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?
  22. 22.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.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?
  25. 25.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  28. 28.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?
  29. 29.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  30. 30.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  32. 32.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  33. 33.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?
  34. 34.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  36. 36.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  39. 39.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  40. 40.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =

Answer key

  1. 902
  2. 759
  3. 825
  4. 1122
  5. 1111
  6. 1122
  7. 1111
  8. 616
  9. 693
  10. 781
  11. 396
  12. 1012
  13. 671
  14. 231
  15. 319
  16. 451
  17. 1034
  18. 1012
  19. 682
  20. 847
  21. 770
  22. 946
  23. 253
  24. 957
  25. 803
  26. 1199
  27. 792
  28. 572
  29. 759
  30. 836
  31. 924
  32. 968
  33. 484
  34. 759
  35. 704
  36. 924
  37. 902
  38. 561
  39. 737
  40. 1056

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