How to explain fractions and mixed numbers to my 4th grader?

Li buys supplies so he can make and sell key chains. he begins to make a profit only after he sells 4 key chains. what point on the graph makes the most sense in this situation?

In the triangles, bc =de and ac fe.if the mzc is greater than the mze, then ab isdfelth

Louis wants to carpet the rectangular floor of his basement.the basement has an area of 864 square feet.the width of the basement is 2/3 it's length. what is the length of louis's basement