What is 21(5 × 10 + 7)?

What is (39 × 11 + 9) ÷ 2?

Is √2 a rational number?

Andrew had $100.00. He spent $39.99 on a pair of jeans, $24.99 on a shirt, and received $20.00 from each of his parents. Then, he spent $19.25 on a cap. How much money does he have now? Show all your work.