Expression HELP! Math trouble...?

Question

I had trouble with this equation: 0.4 - 3 (2 - 1)

So, I looked in the back of the book at the answer which is - 2.6

I don't understand how because I kept getting the answer 7.4

Can you walk me through and explain because if you help me with this expression, I'll basically know how to do the rest.

Thanks beforehand. :o)

Answer 1

You have to follow order of operations which says that you do what is in the parentheses first.

Then you would do any multiplication or division.

Finally, you would do any addition or subtraction.

For your problem you would find 2-1 because it's in parentheses. Then you would multiply the answer by 3 because it's right outside the parentheses. Then you would subtract that answer from 0.4.

I'm guessing you'll get -2.6.

Answer 2

Sure buddy! no problem i will be glad to help. first of all let's take a look at the expression, you mentioned equation which is not the write term, since a mathematical equation contains two values that equal each other and are seperated by an equal sign, i know i shouldn't be giving you a full lecture but this knowledge will come handy. ok so your basically told to solve the given expression below:

0.4-3(2-1)
well, first of all you will need to have some knowledge of the order of operations. in the mathematical community we use a simple device PEMDAS, first you perform all the operations in parentheses, then you do all the exponents , then you multiply or divide from left to right and finally you add or subtract from left to right. so in this equation the first step is to perform (2-1) since it is in parentheses, so, 2-1=1 next multiply -3 times 1 is -3. now the expression your left with is 0.4-3 which gives you -2.6 hence the answer in your text.

well good luck! i hope i was able to help you.

Answer 3

The way we we taught this is to remeber the imaginary word BIDMAS

B - Brackets
I - Indices (to the power)
D - Division
M - Mulitipication
A - Addition
S - Subtraction

Although, the D and M, and A and S can be swapped round.

0.4-3(2-1) can also be written as
0.4-3*(2-1) (it helped me to start with putting the times in!)

So
You have to do the
Contents of the BRACKETS First
2-1=1

Then the MULTIPICATION
3*1=3 The 1 is from the brackets

then SUBTRACT
0.4-3=2.6

Answer 4

o.4-3(2-1)=0.4-3(1)
=0.4-3=-3+0.4
when you add two nos with
different signs the rule
is subtract the smaller absolute
value froem the bigger absolute
value and to the result give the
sign of the bigger absolute value
so 3-0.4=2.6 and since 3 has a
negative sign the answer would be -2.6

Answer 5

Hi there

.4 - 3 = -2.6 and 2 - 1 = 1

I assume this question is supposed to make you remember your order of operations. Solve each of those two questions first
(.4 - 3) and (2 - 1) and then multiply the result that you get from each one.

(-2.6) x (1) = ... your answer!

Good luck!

Answer 6

Step 1:

2-1 Answer is: 1

Step 2:

Multiply 3 times 1 Answer is: 3

Step 3:

0.4 minus 3 equals -2.6

TA DA!

Answer 7

remember order of operations (Please excuse my dear aunt sally PEMDAS) anything in Parenthesis should be done first, then Exponents, then Multiplication and Division last Addition and Subtraction.
In you question 2-1 should be done first = 1
then 3 x 1 = 3
last 0.4 - 3 = -2.6