Simplify the expression $2t+4\times8t$2t+4×8t.
Simplify the expression $12s-8s\div4$12s−8s÷4.
Simplify the expression $12u\div3-2u$12u÷3−2u.
Simplify the expression $\left(5u-2u\right)\times3$(5u−2u)×3.