He showed understanding towards my explanation.

The profits of this company increase and decrease every year.

Population fluctuations greatly affect the economic situation.

This year's sales increased by 20% compared to last year.

This year's sales increased by 20% compared to last year.

This pie chart shows the company's sales.

This chart shows the increase and decrease in sales.

The theory of directed graphs is a branch of mathematics.

Graph theory is a branch of mathematics that studies mathematical structures called graphs.

This bar graph shows the sales of each product.