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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 78 · 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. 1.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  2. 2.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  3. 3.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?
  4. 4.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?
  5. 5.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  6. 6.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?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  9. 9.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  11. 11.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  12. 12.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  13. 13.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?
  14. 14.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  15. 15.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?
  16. 16.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  18. 18.A leapfrog list starts 2, 5 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): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  21. 21.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  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. 23.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  24. 24.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?
  25. 25.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  28. 28.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?
  29. 29.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  30. 30.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?
  31. 31.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  32. 32.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  34. 34.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  35. 35.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?
  36. 36.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  38. 38.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?
  39. 39.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  40. 40.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 759
  2. 814
  3. 759
  4. 605
  5. 671
  6. 231
  7. 308
  8. 1023
  9. 1067
  10. 473
  11. 847
  12. 638
  13. 825
  14. 396
  15. 143
  16. 792
  17. 1056
  18. 550
  19. 704
  20. 583
  21. 374
  22. 550
  23. 198
  24. 715
  25. 341
  26. 935
  27. 198
  28. 638
  29. 616
  30. 781
  31. 682
  32. 913
  33. 484
  34. 143
  35. 693
  36. 528
  37. 660
  38. 286
  39. 583
  40. 693

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