Knowing that 1 yards its 36 inch first we have to multiply 3 times 36 to get much much wood Ms. Jones has.
36*3=108 inches
Finally we have to divide 108 : 18 3/8 to get the answer.
108:

When we want to subtract number by fraction we can multiply number by inverse of that fraction, so

We have to round down the result, so the answer is 5.