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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 472 · 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. 1.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  2. 2.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  3. 3.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  4. 4.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?
  5. 5.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?
  6. 6.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  7. 7.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  11. 11.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  12. 12.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  18. 18.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  20. 20.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?
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  23. 23.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  25. 25.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?
  26. 26.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  27. 27.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  29. 29.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?
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  34. 34.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?
  35. 35.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 1144
  2. 1232
  3. 1001
  4. 396
  5. 671
  6. 957
  7. 759
  8. 671
  9. 418
  10. 341
  11. 1111
  12. 715
  13. 583
  14. 506
  15. 253
  16. 627
  17. 902
  18. 550
  19. 198
  20. 869
  21. 671
  22. 946
  23. 1023
  24. 759
  25. 638
  26. 253
  27. 319
  28. 638
  29. 902
  30. 715
  31. 253
  32. 902
  33. 374
  34. 231
  35. 825
  36. 737
  37. 1001
  38. 759
  39. 1287
  40. 825

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