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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 27 · 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 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  3. 3.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  4. 4.A leapfrog list starts 5, 4 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 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  7. 7.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  8. 8.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?
  9. 9.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?
  10. 10.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  15. 15.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  18. 18.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  20. 20.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?
  21. 21.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  23. 23.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?
  24. 24.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  26. 26.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  27. 27.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?
  28. 28.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  32. 32.A leapfrog list starts 5, 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 4, 4 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 5, 6 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): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  36. 36.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  37. 37.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  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.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?

Answer key

  1. 286
  2. 363
  3. 319
  4. 627
  5. 253
  6. 495
  7. 451
  8. 583
  9. 341
  10. 759
  11. 935
  12. 396
  13. 1287
  14. 484
  15. 957
  16. 253
  17. 143
  18. 407
  19. 847
  20. 1177
  21. 759
  22. 792
  23. 473
  24. 759
  25. 418
  26. 638
  27. 682
  28. 561
  29. 627
  30. 1067
  31. 847
  32. 539
  33. 572
  34. 803
  35. 1111
  36. 935
  37. 143
  38. 1122
  39. 495
  40. 726

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