Answer :
Final answer:
The correct expression for 'multiply the sum of 7 and 6 by the sum of 4 and 5' is (option b.) (7 + 6) x (4 + 5). The parentheses indicate that addition should be performed before multiplication, complying with the order of operations.
Explanation:
The correct numerical expression for "multiply the sum of 7 and 6 by the sum of 4 and 5" is option b, which is presented as (7 + 6) x (4 + 5).
This expression requires us to first find the sums within each set of parentheses before multiplying them together. This is because the parentheses indicate that we should perform the addition operations before the multiplication, which aligns with the order of operations in mathematics (often remembered by the acronym PEMDAS - Parentheses, Exponents, Multiplication and Division, Addition and Subtraction).
The incorrect options do not respect the intended order of operations implied by the phrasing of the question. For example, option a, 7 + 6 x 4 + 5, would result in performing the multiplication before addition due to the absence of parentheses, thus giving an incorrect result based on the question's requirement.
