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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 774 · 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, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  2. 2.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  3. 3.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  5. 5.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?
  6. 6.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?
  7. 7.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  9. 9.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  10. 10.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  11. 11.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.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?
  13. 13.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  15. 15.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  16. 16.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  17. 17.A leapfrog list starts 7, 7 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 2, 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): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  20. 20.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?
  21. 21.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.A leapfrog list starts 4, 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 3, 3 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): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  26. 26.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  27. 27.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  28. 28.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  29. 29.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  35. 35.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  36. 36.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  37. 37.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  39. 39.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?
  40. 40.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?

Answer key

  1. 803
  2. 792
  3. 946
  4. 1023
  5. 858
  6. 1287
  7. 869
  8. 561
  9. 869
  10. 363
  11. 583
  12. 1232
  13. 1144
  14. 979
  15. 671
  16. 396
  17. 1001
  18. 462
  19. 396
  20. 528
  21. 726
  22. 781
  23. 1012
  24. 429
  25. 484
  26. 1089
  27. 143
  28. 737
  29. 671
  30. 913
  31. 715
  32. 484
  33. 231
  34. 913
  35. 1067
  36. 836
  37. 363
  38. 847
  39. 572
  40. 902

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