To show the work:
68 ÷ 0.4 = 170
Step-by-step explanation:
You can think of dividing by a fraction as multiplying by its reciprocal. The reciprocal of 0.4 is 1/0.4.
So instead of dividing 68 by 0.4, you can multiply it by 1/0.4, which is the same as multiplying by 2.5.
68 * 2.5 = 170