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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 953 · 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, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  10. 10.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?
  11. 11.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  12. 12.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  13. 13.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  14. 14.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  16. 16.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  17. 17.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  19. 19.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?
  20. 20.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  21. 21.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  22. 22.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  24. 24.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?
  25. 25.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?
  26. 26.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  27. 27.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  28. 28.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?
  29. 29.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?
  30. 30.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  31. 31.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?
  32. 32.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  34. 34.A leapfrog list starts 8, 7 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, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  36. 36.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  37. 37.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  38. 38.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?
  39. 39.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  40. 40.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =

Answer key

  1. 583
  2. 319
  3. 1232
  4. 825
  5. 286
  6. 539
  7. 462
  8. 253
  9. 682
  10. 319
  11. 253
  12. 715
  13. 891
  14. 737
  15. 759
  16. 1067
  17. 770
  18. 517
  19. 198
  20. 1056
  21. 363
  22. 627
  23. 880
  24. 858
  25. 506
  26. 407
  27. 418
  28. 1287
  29. 902
  30. 968
  31. 374
  32. 1144
  33. 748
  34. 1056
  35. 418
  36. 506
  37. 1199
  38. 957
  39. 451
  40. 935

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