Today’s quick grammar lesson is inspired by one of my childhood heroes: Count von Count*. We’re going to explore numbers and how they should be formatted depending on context. Unlike other formatting rules, writing numbers is actually quite straight forward.

The Gist of It

For numbers 10 and above, use the figure. This means using 11 for eleven, 25 for twenty-five and so on. Any number below 10 should be spelled out; for example, two microscopes, three petri dishes and “four beautiful bats (uh, uh, uh).”*

These two rules apply even if one sentence contains a combination of numbers; for example, Oscar’s trash can contained two banana peels, 15 bent bicycle wheels, three cracked hockey sticks and 22 smashed vinyl records.

Exception: These rules can and should be broken when writing times, temperatures, addresses, decimals, votes, scores, rulings, monetary units, dates and years.

Generally, it is best practice to avoid starting a sentence with a number. If this cannot be avoided, you should spell out the entire number even if it is above 10. Here’s an example:

Seventy-seven per cent of dolphins surveyed said they preferred sashimi tuna over cooked tuna.

If you must spell out numbers between 21 and 99, be sure to add a hyphen between the two digits; for example: Eighty-four or 84 elephants listened to a classical music concert and enjoyed it.

Being Casual

If you are writing out large numbers in an informal manner, it’s best to spell out the number instead of using the figure; for example, there were millions of fallen apples on the grass, or billions of fireflies danced in the night sky.

The End

See, formatting numbers isn’t all that scary once you get the gist of it, especially if you picture Count von Count surrounded by “four beautiful bats.”