Composite numbers

The first instance of  is under the 4th Grade Math Mission. This exercise practices recognition of composite numbers.

Types of Problems
There is one type of problem in this exercise:


 * 1) Find the composite number: This problem lists five numbers and asks the student to select the one that is a composite number.Compnum.png

Strategies
This exercise is easy to get accuracy and speed badges because standard divisibility rules can be used to quickly discover which numbers are composite.


 * 1) The questions are multiple choice so there is only one correct answer. Once you find it, don't bother checking the other possibilities.
 * 2) You can use this exercise to practice recognizing primes more easily, since each problem also lists four prime numbers.
 * 3) 91 is composite.