1. Mary held up a sheet of paper. "Do you want to keep this?" she asked her husband. "It's got our house number and a lot of figures all over it." "That's right. Something I worked out on our number, but you can throw it away," replied Ben. "It happens to be exactly 33 times the sum of its digits." Believe it or not! But what was the number?

The number was 561

The number was 594

The number was 693