Insert parentheses to make this true

12 ÷ 2 ∙ 9 ÷ 3 ∙ 2 + 3 = 13

Sorry - can't be done.

13 is prime, so since all the operations except the +3 are multiply/divide, the +3 must be on its own. That means that

(12 ÷ 2 ∙ 9 ÷ 3 ∙ 2) + 3 = 13
and 12 ÷ 2 ∙ 9 ÷ 3 ∙ 2 = 10
But, 5 is a factor of 10, but is not a factor of any number on the left.

To insert parentheses to make the equation true, let's follow the order of operations (PEMDAS/BODMAS):

12 ÷ 2 ∙ 9 ÷ 3 ∙ 2 + 3 = 13

Step 1: Start with the multiplication and division from left to right.

12 ÷ 2 = 6

6 ∙ 9 ÷ 3 ∙ 2 + 3 = 13

Step 2: Continue with the multiplication and division.

6 ∙ 9 = 54

54 ÷ 3 ∙ 2 + 3 = 13

Step 3: Perform the multiplication.

54 ÷ 3 = 18

18 ∙ 2 + 3 = 13

Step 4: Perform the remaining multiplication.

18 ∙ 2 = 36

36 + 3 = 39

The equation is not true when following the given order of operations. Therefore, it is not possible to insert parentheses in this equation to make it equal to 13.