We need to write an expression for "add 34 and 6 and then multiply 3"
"Add" represents + operation .
"multiply" represents × operation.
We need to add 34 and 6.
So, we can write 34+6 and then we need multiply the sum by 3.
So, we need to keep above addition of 34 and 6 in parantehsis. We get
(34+6) × 3.
So, the final expression is (34+6) × 3.