Parentheses in simple Order of Operations: Two Pairs of Parentheses

Let's simplify this expression whilst following the order of operations. Exponents precede multiplication and division, which in turn precede addition and subtraction, and parentheses precede all of the above,

Therefore, we'll start by simplifying the expressions inside of the parentheses first:
$(9+7+3)(4+5+3)(7-3-4)= \\ 19\cdot12\cdot0$

Now we'll calculate the multiplication result step by step from left to right, remembering also that multiplying any number by 0 gives a result of 0:

$19\cdot12\cdot0 =\\ 228\cdot0 =\\ 0$

Since the commutative property of multiplication applies, and in the expression we simplified above there is multiplication between all terms, the order of operations in this calculation doesn't matter (it's not necessary to perform the leftmost multiplication first etc. as we did), however, it is recommended to practice performing operations from left to right as this is the natural order of arithmetic operations (in the absence of parentheses, or other preceding arithmetic operations according to the order of operations mentioned at the beginning of this solution)

Therefore, the correct answer is answer B.

Let's simplify this expression whilst following the order of operations. Exponents precede multiplication and division, which in turn precede addition and subtraction, and that parentheses precede all of the above:

Therefore, we'll start by simplifying the expressions inside of the parentheses first:
$(7-4-3)(15-6-2)+3\cdot5\cdot2= \\ 0\cdot7+3\cdot5\cdot2=$

We'll continue to perform the multiplications in the two terms we obtained in the expression in the last stage, this is because multiplication comes before addition. In each term we'll perform the multiplications step by step from left to right, also remember that multiplying any number by 0 gives a result of 0:

$0\cdot7+3\cdot5\cdot2= \\ 0+15\cdot2= \\ 30$

Note that since the commutative property of multiplication applies, and in the second term from the left in the expression we simplified above there is multiplication between all terms, the order of operations in this calculation doesn't matter (it's not necessary to perform the left multiplication first etc. as we did), however it is recommended to practice performing operations from left to right as this is the natural order of arithmetic operations (in the absence of parentheses, or other preceding arithmetic operations according to the known order of operations mentioned at the beginning of this solution)

Therefore the correct answer is answer D.

This simple rule is the order of operations which states that multiplication and division come before addition and subtraction, and operations enclosed in parentheses come first,

In the given example of division between two given numbers in parentheses, therefore according to the order of operations mentioned above, we start by calculating the values of each of the numbers within the parentheses, there is no prohibition against calculating the result of the addition operation in the given number, for the sake of proper order, this operation is performed later:

$(3+2-1):(1+3)-1+5= \\ 4:4-1+5$In continuation of the principle that division comes before addition and subtraction the division operation is performed first and then the operations of subtraction and addition which were received in the given number and in the last stage:

$4:4-1+5= \\ 1-1+5=\\ 5$Therefore the correct answer here is answer B.