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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 733 · 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): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  2. 2.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?
  3. 3.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  4. 4.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  5. 5.A leapfrog list starts 7, 4 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 3, 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): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  8. 8.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?
  9. 9.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?
  10. 10.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  11. 11.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?
  12. 12.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  13. 13.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?
  14. 14.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  15. 15.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?
  16. 16.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?
  17. 17.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.A leapfrog list starts 6, 4 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): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  21. 21.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  22. 22.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  23. 23.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  24. 24.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  25. 25.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  26. 26.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  27. 27.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  28. 28.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?
  29. 29.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  30. 30.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.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?
  39. 39.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  40. 40.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?

Answer key

  1. 1067
  2. 1199
  3. 759
  4. 836
  5. 737
  6. 957
  7. 319
  8. 946
  9. 198
  10. 616
  11. 957
  12. 1144
  13. 1111
  14. 253
  15. 253
  16. 286
  17. 627
  18. 682
  19. 902
  20. 594
  21. 660
  22. 572
  23. 1199
  24. 1034
  25. 550
  26. 583
  27. 627
  28. 737
  29. 1012
  30. 814
  31. 847
  32. 407
  33. 814
  34. 143
  35. 396
  36. 583
  37. 781
  38. 627
  39. 671
  40. 880

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