Math Is Fun Forum

GeeGee

Member

Registered: 2008-09-27

Posts: 7

I don't understand my homework {powers}

Well at scool we are learning to the power of [example 5²] and i have a test on monday! Can you explain it to me in a unconfusing way!!!

from

GeeGee.

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: I don't understand my homework {powers}

The little number tells you how many times to multiply the big number by itself.
So:

5¹ = 5
5² = 5 x 5 = 25
5³ = 5 x 5 x 5 = 125

etc.

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It wanted to be normal.

GeeGee

Member

Registered: 2008-09-27

Posts: 7

Re: I don't understand my homework {powers}

But when i've got 3³÷2²-1² what do i do.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 46,406

Re: I don't understand my homework {powers}

When different mathematical operations such as Power, Division, Multiplication, Addition and Subtraction are given without being being separate by brackets, the power operation has to be first performed, followed by division/multiplication, then by addition/subtraction.

The problem you have been given is 3³÷2²-1².
First evaluate the powers.
3³ = 3 x 3 x 3 = 9 x 3 = 27;
2² = 2 x 2 = 4
1² = 1 x 1
I guess you have mentioned the question wrongly.
It should have been
3³÷(2²-1²).
Since we know 3³ is 27, lets find out what (2²-1²) is. We have seen 2² is 4 and 1² is 1. therefore, 4-1=3.
When 27 is divided by 3, you get 9. That is the answer!

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