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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 584 · 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  2. 2.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  3. 3.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  5. 5.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?
  6. 6.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  7. 7.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  8. 8.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?
  9. 9.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?
  10. 10.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  11. 11.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  12. 12.A leapfrog list starts 3, 9 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 9, 2 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): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  15. 15.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  16. 16.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  18. 18.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.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?
  21. 21.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  22. 22.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  23. 23.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.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?
  26. 26.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  29. 29.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?
  30. 30.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  31. 31.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  36. 36.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  37. 37.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  38. 38.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  40. 40.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?

Answer key

  1. 1056
  2. 726
  3. 781
  4. 396
  5. 869
  6. 935
  7. 1111
  8. 550
  9. 506
  10. 715
  11. 1177
  12. 957
  13. 671
  14. 660
  15. 308
  16. 836
  17. 671
  18. 671
  19. 253
  20. 737
  21. 847
  22. 583
  23. 748
  24. 946
  25. 759
  26. 1034
  27. 473
  28. 528
  29. 671
  30. 913
  31. 924
  32. 286
  33. 924
  34. 1001
  35. 319
  36. 1056
  37. 583
  38. 506
  39. 143
  40. 891

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