Week 4: Arithmetic operators

Python can work like a calculator. It adds, subtracts, multiplies and divides numbers, and the percent sign gives you the remainder after division. This week’s focus is the operators +, -, *, /, = and %. Type each one slowly and accurately.

What you will learn

On the US English layout, the six symbols are typed like this:

• + is the = key held with Shift. Hold Shift with the opposite pinky and press = with the right pinky.
• - is the - key, pressed with the right pinky.
• * is the 8 key held with Shift. Hold Shift with the opposite pinky and press 8 with the right middle finger.
• / is the / key, pressed with the right pinky.
• = is the = key, pressed with the right pinky.
• % is the 5 key held with Shift. Hold Shift with the opposite pinky and press 5 with the left index finger.

Here are two lines that use these operators:

print(7 + 3)
print(10 % 3)

The first line prints 10. The second prints 1, which is the remainder when 10 is divided by 3. Spaces around the operators make the line easier to read.

Technique tips

• For symbols that need Shift, press Shift with the opposite pinky first, then the symbol key.
• Keep the reach to - and / short. Both are pressed with the right pinky, so let that finger move only as far as needed.
• The 8 and 5 keys sit on the number row. Lift the finger, type the symbol, and return to the home row straight away.
• Say each operator in your head as you type it: plus, minus, star, slash, equals, percent.

Lessons

1. Lesson 1 (10 to 15 minutes): Learn. Watch the keyboard demo for all six symbols. Then type print(7 + 3) slowly.
2. Lesson 2 (10 to 15 minutes): Practice. Repeat lines such as print(10 % 3), print(8 * 2) and print(9 / 3). Check that each symbol is the one you meant.
3. Lesson 3 (10 to 15 minutes): Review. Take the 2-minute test built from this week’s operators. Note the symbol that gave you the most trouble and focus on it in the next session.

This week’s goal

The goal is 14 wpm with 91% accuracy. The first star comes when you finish the lessons. The second star comes at 91% accuracy, and the third when you also reach 14 wpm. A wrong operator changes the result of the whole line, so accuracy comes before speed.