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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 625 · 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): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  3. 3.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?
  4. 4.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?
  5. 5.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  6. 6.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?
  7. 7.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?
  8. 8.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  9. 9.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  11. 11.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  12. 12.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  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. 14.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  15. 15.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  18. 18.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?
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  23. 23.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  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.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?
  28. 28.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?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  31. 31.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  32. 32.A leapfrog list starts 2, 2 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 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.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?
  36. 36.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  37. 37.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?
  38. 38.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  39. 39.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?
  40. 40.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =

Answer key

  1. 759
  2. 1144
  3. 528
  4. 143
  5. 913
  6. 770
  7. 506
  8. 847
  9. 253
  10. 682
  11. 836
  12. 539
  13. 198
  14. 1287
  15. 396
  16. 847
  17. 814
  18. 913
  19. 693
  20. 957
  21. 1177
  22. 1012
  23. 1111
  24. 825
  25. 539
  26. 671
  27. 583
  28. 968
  29. 979
  30. 253
  31. 1067
  32. 286
  33. 451
  34. 704
  35. 858
  36. 1199
  37. 1012
  38. 979
  39. 902
  40. 583

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