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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 479 · 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 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  2. 2.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  3. 3.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  4. 4.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.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?
  6. 6.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?
  7. 7.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  9. 9.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  10. 10.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  12. 12.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?
  13. 13.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  15. 15.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  25. 25.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  26. 26.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  27. 27.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  28. 28.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?
  29. 29.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?
  30. 30.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  31. 31.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  32. 32.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  33. 33.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  36. 36.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  37. 37.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?
  38. 38.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 363
  2. 979
  3. 550
  4. 363
  5. 1199
  6. 286
  7. 517
  8. 308
  9. 1144
  10. 638
  11. 429
  12. 957
  13. 935
  14. 913
  15. 143
  16. 1034
  17. 737
  18. 946
  19. 660
  20. 506
  21. 748
  22. 1111
  23. 1232
  24. 495
  25. 638
  26. 374
  27. 484
  28. 506
  29. 759
  30. 198
  31. 957
  32. 814
  33. 671
  34. 396
  35. 902
  36. 1067
  37. 924
  38. 748
  39. 550
  40. 1144

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