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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 232 · 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. 1.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  2. 2.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  4. 4.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?
  5. 5.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  6. 6.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  9. 9.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  10. 10.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.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?
  13. 13.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  23. 23.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  24. 24.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?
  25. 25.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  27. 27.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  28. 28.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  32. 32.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?
  33. 33.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?
  34. 34.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  35. 35.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  37. 37.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  38. 38.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  39. 39.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  40. 40.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =

Answer key

  1. 759
  2. 550
  3. 748
  4. 715
  5. 319
  6. 814
  7. 1111
  8. 429
  9. 847
  10. 319
  11. 407
  12. 583
  13. 1111
  14. 1023
  15. 561
  16. 198
  17. 704
  18. 858
  19. 1012
  20. 704
  21. 979
  22. 605
  23. 715
  24. 957
  25. 968
  26. 1067
  27. 495
  28. 638
  29. 539
  30. 759
  31. 231
  32. 682
  33. 308
  34. 1232
  35. 253
  36. 891
  37. 1144
  38. 869
  39. 583
  40. 847

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