Associative Property: Addition, subtraction, multiplication and division

According to the order of operations, we solve the exercise from left to right since the only operation in the exercise is division:

$24:8=3$

$3:3=1$

According to the rules of the order of operations, we first solve the multiplication exercise:

$4\times2=8$

Now we obtain the exercise:

$8-5+4=$

We solve the exercise from left to right:

$8-5=3$

$3+4=7$

According to the rules of the order of operations, we first solve the division exercise:

$6:2=3$

Now we get the exercise:

$-5+2-3=$

We solve the exercise from left to right:

$-5+2=-3$

$-3-3=-6$

According to the order of operations, we first solve the division exercise, and then the subtraction:

$(6:2)+9-4=$

$6:2=3$

Now we place the subtraction exercise in parentheses:

$3+(9-4)=$

$3+5=8$

According to the rules of the order of operations, we first solve the division exercise:

$9:3=3$

Now we obtain the exercise:

$3-3=0$

We can use the substitutive property to reorder and make solving the equation simpler:

$\frac{2}{5}+\frac{3}{5}-2=$

We first add the fractions:

$\frac{2+3}{5}=\frac{5}{5}=1$

Now we obtain the exercise:

$1-2=-1$

According to the rules regarding the order of arithmetic operations, we first solve the multiplication exercise:

$5\times4=20$

We obtain the following exercise:

$3+4-20=$

We then solve the exercise from left to right:

$3+4=7$

$7-20=-13$

To solve this expression, we need to follow the order of operations: Parentheses, Exponents (not in this problem), Multiplication and Division (from left to right), Addition and Subtraction (from left to right).

Start with the parentheses: $(2+1) = 3$

Substitute back into the expression: $8+5-6\times3+7$

Then, perform the multiplication: $6\times3 = 18$

Substitute back into the expression: $8+5-18+7$

Next, perform the addition and subtraction from left to right:

$8+5 = 13$

Then: $13-18 = -5$

Finally: $-5+7 = 2$

So, the final answer is $2$.

Given that in the exercise there is only multiplication, we add 9 and 7 to the numerator of the fraction as follows:

$\frac{9\times7\times3}{9}=$

We simplify the 9 in the numerator and denominator, and obtain:

$7\times3=21$

We simplify this expression paying attention to the order of operations which states that exponentiation comes before multiplication and division, and before addition and subtraction, and that parentheses precede all of them.

Therefore, we start by performing the multiplication within parentheses, then we carry out the division operation, and we finish by performing the subtraction operation:

$9-6:(4\cdot3)-1= \\ 9-6:12-1= \\ 9-0.5-1= \\ 7.5$

Therefore, the correct answer is option C.

First, we will find the sum of the fractions:

$\frac{3}{7}+\frac{4}{7}=\frac{3+4}{7}=\frac{7}{7}=1$

Now we get the exercise:

$2+1=3$

According to the order of operations rules, we first insert the multiplication and division exercises into parentheses:

$2+(4\times5:2)+3=$

Now let's solve the expression in parentheses from left to right:

$4\times5=20$

$20:2=10$

And we get the expression:

$2+10+3=$

Let's solve the expression from left to right:

$2+10=12$

$12+3=15$

According to the order of operations, we place the multiplication and division exercise in parentheses:

$(12:4)-3+(3\times3)=$

We solve the exercises in parentheses:

$12:4=3$

$3\times3=9$

And we obtain the exercise:

$3-3+9=$

According to the order of operations, we solve the exercise from left to right:

$3-3=0$

$0+9=9$

According to the rules of the order of arithmetic operations, we will begin by enclosing the multiplication and division exercises inside of parentheses:

$(25:5)+(4\times3)-5=$

We then proceed to solve the exercises in the parentheses:

$25:5=5$

$4\times3=12$

We obtain the following:

$5+12-5=$

To finish we solve the exercise from left to right:

$5+12=17$

$17-5=12$

According to the order of operations rules, we first insert the multiplication and division exercises into parentheses:

$3+(4:2\times1)-9+4=$

We'll solve the exercise from left to right:

$4:2=2$

$2\times1=2$

And we'll obtain the following exercise:

$3+2-9+4=$

Since the exercise only contains subtraction operations, we'll solve it from left to right:

$3+2=5$

$5-9=-4$

$-4+4=0$

We add the 2 to the numerator of the fraction in the multiplication exercise, and the 4 in the denominator of the fraction we break it down into a smaller multiplication exercise:

$5-\frac{2\times3}{2\times2}=$

We simplify the 2 in the numerator and denominator:

$5-\frac{3}{2}=$

We convert the simple fraction into a mixed fraction:

$5-1\frac{1}{2}=3\frac{1}{2}$

According to the rules of the order of arithmetic operations, we must first place the multiplication and division exercises inside of parentheses:

$7+(21:7\times4)+3-9=$

We then proceed to solve the exercise inside of the parentheses from left to right:

$21:7=3$

$3\times4=12$

Which results in the following exercise:

$7+12+3-9=$

We then finish by solving the exercise from left to right:

$7+12=19$

$19+3=22$

$22-9=13$

We can use the substitutive property and arrange the exercise in a way that makes solving the exercise simpler:

$-2+4+3+4a-2a-2a=$

First, we solve the addition exercise:

$4+3=7$

We now obtain the exercise:

$-2+7+4a-2a-2a=$

We add the coefficients a:

$4a-2a=2a$

$2a-2a=0$

We now obtain the exercise:

$-2+7+0=$$$

We use the substitutive property:

$7-2+0=5+0=5$

We can use the substitutive property and rearrange the exercise in a way that makes it easier for us to solve the exercise:

$2a-a+3-2=$

We solve the exercise from left to right:

$2a-a=a$

$3-2=1$

Therefore, we obtain:

$a+1$

Let's simplify this expression while following the order of operations which states that exponents come before multiplication and division, which come before addition and subtraction, and that parentheses come before all of them,

therefore we'll start by simplifying the expressions in parentheses first:
$4:2\cdot(5+4+6)= \\ 4:2\cdot15$Note that between multiplication and division operations there is no defined precedence for either operation, so we'll calculate the result of the expression obtained in the last stage step by step from left to right (which is the regular order in arithmetic operations), meaning we'll first perform the division operation, as it appears first from the left, and then we'll perform the multiplication operation that comes after it:

$4:2\cdot15 =\\ 2\cdot15 =\\ 30$Therefore the correct answer is answer B.