Number Rules Part 1

January 31, 2017

Dr. Kathryn Sobek, Filipodia Editor


I’m not talking about mathematics! I’m talking about writing about numbers! Here are some quick tips for writing about numbers.

Spell out a number at the beginning of the sentence. For example, ‘20 patients were diagnosed’ should be written as ‘Twenty patients were diagnosed.’ If the start of the sentence is a number that would be quite long written out (e.g. 12,345), then consider rewriting the sentence. For example, ‘12,345 genes were identified during the initial analysis’ could be rewritten as ‘The initial analysis identified 12,345 genes.

If a number is a unit of measure, then don’t spell it out. Numbers that are followed by a percent sign (%) or a unit of measure (mg/mL, °C, nM, etc.) are not written out. For example, ‘The cells were incubated in Drug X (20 mg/mL) at 37 °C for 45 minutes.’

Come back in two weeks for the remaining rules!