Calculate the expressions to compare the values:

a)  of  

b)  of  

c)  of  

Therefore (b) is smaller than (a), which is smaller than (c).

 is 30% of 12, and the decimal equivalent of 30% is 0.3. Therefore, 

 is 40% of 9, and the decimal equivalent of 40% is 0.4. Therefore, 

 is 50% of 6, and the decimal equivalent of 40% is 0.4. Therefore, 

Therefore, .

Of the four choices, only  is a correct statement.

To add two fractions, first express them in terms of the same denominator; the least common denominator of 3 and 6 is 6, so multiply both halves of the first fraction by 2:

Add the numerators and preserve the common denominator:

Reduce by dividing both halves by their greatest common factor, 3:

To multiply two fractions, multiply numerators and multiply denominators:

To divide two fractions, multiply the first number by the reciprocal of the second number - switch the two halves of the latter:

Again, multiply numerators and multiply denominators:

Compare the fractions by expressing them in terms of the same denominator. The least common multiple of 2, 3, and 6 is 6; rewrite each fraction by multiplying whatever number yields this common denominator:

Compare fractions with the same denominator by comparing numerators:

, so

, and

.

Of the four choices, only  is a correct statement.

 is ten added to the square of ten - that is,

Evaluate this according to the order of operations by squaring, then by adding.

Evaluate the other two expressions using the same order:

 is twenty added to the square of nine, so

 is thirty added to the square of eight, so

, so the only correct statement of the four is .

By the order of operations, multiplication precedes either addition or subtraction, so calculate accordingly:

, 

so the only correct statement among the choices is .

.

Each expression can be calculated according to the order of operations: Multiplication and division in left to right order, then addition and subtraction in left to right order.

Divide first:

Multiply second:

Add last:

Multiply first:

Divide second:

Add last:

Multiply first:

Divide second:

Add last:

The only correct statement among the choices is .

30% of a number is equal to that number multiplied by the decimal equivalent of 30%, which is 0.30, or 0.3:

 is 30% of 40, so

Similarly,

 is 20% of 60, so

 is 10% of 80, so

.

The only correct statement of the four is .

In each expression, substitute, then evaluate. Follow the order of operations, which dictates that multiplication precedes subtraction:

The only correct choice is .

In each expression, substitute, then evaluate. Follow the order of operations, which dictates that multiplication precedes addition; also keep in mind that the product of two negative numbers is equal to the product of the corresponding positive numbers:

, so of the four choices, only  is correct.