(-8.3)(5)(-7)= ?

Question

I am not allowed to use Calculator!

Answer 1

This is a standard multiplication problem, with three factors. Notice that two of the factors are negative, which in the end will cancel each other out ... producing a positive answer!

(Rule: Any even number of negatives multiplied together will result in a positive.)

Get out your calculator and let's go:

(-8.3) * 5 * (-7) = 290.5

One important feature of this problem was the omission of the * (or 'times') symbol. Instead, the factors were enclosed within parentheses, and simply written next to one another.

You are presumed to understand this means "multiply these."

Without a calculator, another way to perform the multiplication is to multiply the 'easy' numbers (two at a time). For instance:

5 * -7 is 'easy' ... the product is -35.

Now, the problem becomes:

-8.3 * -35

Here's how I do it:

First, I allow the "negative signs" to cancel each other out.

= 8.3 * 35

For convenience, I might also temporarily "forget" that the decimal exists in the factor 8.3 (I can "put it back again" at the end of the problem ... lose one decimal place now, and get it back again later!).

So, I might do this problem instead:

83
x35
____
2905

Put the decimal point back (one place):

The answer again is 290.5!

Hope this helped!

Answer 2

multyple all numbers first, so 8.3x5x7=290.5
2 negatives x one positive makes the number positive

Answer 3

- 8.3 X
- 7
-------
58.1 X (this answer is positive because (-)(-) = +
5
-------
290.5
-------

Answer 4

the answer is 290.5

Answer 5

the answer is 290.5

Answer 6

(-8.3x5)x(-7)
=-41.5x-7
=41.5x7
=290.5

Answer 7

290.5

Answer 8

290.5

Answer 9

290.5

Answer 10

thats easy!
the ANSWER is
-290.0
but thats my calcutions.