Are the following like terms: $9y$9y and $10y$10y?
Yes
No
Are the following like terms: $10m$10m and $2n$2n?
Are the following like terms: $2xy$2xy and $4yx$4yx?
Are the following like terms: $4pqr$4pqr and $8qp$8qp?
generalises number properties to operate with algebraic expressions