8.7

### Lecture 5: Parentheses and tables

This assignment is due on Sunday, January 22 at 11:59pm. Submit it using Handin as assignment lecture5. Your submission is only accepted if the message “Handin successful” appears.

#### 1The origin of parentheses

Exercise 1. Put the missing closing parenthesis in the right place:
 (place-image (scale 2 bicycle horizontal-position 150 (empty-scene 300 300))
Put the fixed expression in a comment.

Exercise 2. Answer each problem below with one arithmetic formula. Indent each formula properly.
1. At the market, I bought an apple for \$1 and a sandwich for \$5. What is the total that I spent? The answer to this problem is (+ 1 5), so put this in your Definitions Window:
 (define part1 (+ 1 5))

2. At the market, I bought an apple for \$1 and a sandwich for \$5. Because a sandwich is a prepared food item, it is taxed 7%. What is the total that I spent? Define a constant named part2 with your formula.

3. At the market, I bought a baked apple for \$1 and a sandwich for \$5. Because both are prepared food items, both are taxed 7%. What is the total that I spent? Define a constant named part3 with your formula.

4. At the restaurant, I ordered a baked apple for \$1 and a sandwich for \$5. Both are taxed 7%, and I also decided to pay 20% tip on the amount before tax was added. The tip is not taxed. What is the total that I spent? Define a constant named part4 with your formula.

5. At the restaurant, I ordered a baked apple for \$1 and a sandwich for \$5. Both are taxed 7%, and I also decided to pay 20% tip on the amount after tax was added. What is the total that I spent? Define a constant named part5 with your formula.

6. Like the last probem, but what if I rounded up the final amount to the nearest dollar (using the ceiling function)? Define a constant named part6 with your formula.

#### 2The table method

The Beginning Student Tables tool is available online for your use.

Exercise 3. Use the table method to design a function ctof that converts a temperature in Celsius to a temperature in Fahrenheit. Submit your table as a screenshot, a photo, or a comment.

Exercise 4. Use the table method to design a function combine-digits that combines two digits (each an integer between 0 and 9) into an integer between 0 and 99. The first given digit should become the first digit of the output (in other words, tens). The second given digit should become the second digit of the output (in other words, ones). Submit your table as a screenshot, a photo, or a comment.