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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 692 · 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 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  4. 4.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  5. 5.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?
  6. 6.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  7. 7.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  10. 10.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  11. 11.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  13. 13.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?
  14. 14.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  19. 19.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  21. 21.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  22. 22.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.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?
  26. 26.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?
  27. 27.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  28. 28.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?
  29. 29.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  30. 30.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  31. 31.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  32. 32.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  33. 33.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  37. 37.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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. 40.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =

Answer key

  1. 418
  2. 704
  3. 363
  4. 418
  5. 858
  6. 627
  7. 803
  8. 1012
  9. 484
  10. 649
  11. 671
  12. 968
  13. 198
  14. 528
  15. 605
  16. 143
  17. 759
  18. 638
  19. 924
  20. 341
  21. 1232
  22. 374
  23. 715
  24. 572
  25. 858
  26. 693
  27. 715
  28. 1001
  29. 847
  30. 286
  31. 253
  32. 946
  33. 979
  34. 1177
  35. 473
  36. 1122
  37. 1287
  38. 1122
  39. 550
  40. 308

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