Original sentence: Children's dollhouses are commonly in 1:18 or 2/3" scale (1 foot is represented by 2/3 inch), while dollhouses for adult collectors are usually in a scale of 1:12 (1 inch equals 1 foot)
Edited sentence: Children's dollhouses are commonly in 1:18 or 3/4" scale (1 foot is represented by 3/4 inch), while dollhouses for adult collectors are usually in a scale of 1:12 (1 inch equals 1 foot)