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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 75 · 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.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  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.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  7. 7.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  8. 8.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  9. 9.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  11. 11.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  12. 12.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  13. 13.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  15. 15.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  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 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  19. 19.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?
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  22. 22.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?
  23. 23.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  26. 26.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?
  27. 27.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  28. 28.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  29. 29.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  30. 30.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  31. 31.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  33. 33.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  34. 34.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?
  35. 35.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?
  36. 36.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  37. 37.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  38. 38.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  39. 39.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  40. 40.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?

Answer key

  1. 649
  2. 572
  3. 781
  4. 418
  5. 1144
  6. 605
  7. 858
  8. 759
  9. 759
  10. 803
  11. 253
  12. 363
  13. 858
  14. 143
  15. 638
  16. 286
  17. 902
  18. 506
  19. 528
  20. 1232
  21. 693
  22. 550
  23. 847
  24. 143
  25. 847
  26. 671
  27. 847
  28. 396
  29. 891
  30. 693
  31. 286
  32. 1287
  33. 539
  34. 572
  35. 407
  36. 737
  37. 451
  38. 748
  39. 1111
  40. 1232

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