Math topic中文

Multiplication principle

If a task takes several steps, multiply the counts of each step (counting by stages).

Practice questions

  1. 1Consider all positive four-digit integers consisting of only even digits. What fraction of these integers are not divisi…
  2. 2How many integers between 1000 and 9999 have four distinct digits? A. 3024 B. 4536 C. 5040 D. 6480 E. 6561
  3. 3An integer between 1000 and 9999, inclusive, is chosen at random. What is the probability that it is an odd integer whos…
  4. 4从1～201～20这2020个数字中任取22个不同的数，使它们的和为奇数，有多少种不同的选法？
  5. 5In the small country of Mathland, all automobile license plates have four symbols. The first must be a vowel (AA, EE,…
  6. 6An ATM password at Fred's Bank is composed of four digits from 0 to 9, with repeated digits allowable. If no password ma…