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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 615 · 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): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  2. 2.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  4. 4.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.A leapfrog list starts 4, 3 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): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  12. 12.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  13. 13.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  15. 15.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?
  16. 16.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  18. 18.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  23. 23.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?
  24. 24.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  25. 25.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  26. 26.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?
  27. 27.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?
  28. 28.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  29. 29.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  31. 31.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  33. 33.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  34. 34.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?
  35. 35.A leapfrog list starts 8, 3 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 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 583
  2. 759
  3. 770
  4. 495
  5. 484
  6. 825
  7. 913
  8. 1089
  9. 561
  10. 506
  11. 583
  12. 792
  13. 418
  14. 803
  15. 759
  16. 473
  17. 616
  18. 935
  19. 682
  20. 407
  21. 319
  22. 913
  23. 693
  24. 649
  25. 957
  26. 946
  27. 374
  28. 319
  29. 715
  30. 682
  31. 308
  32. 572
  33. 495
  34. 198
  35. 704
  36. 902
  37. 1056
  38. 1232
  39. 341
  40. 902

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