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(7*8)^2/10 changed into a decimal

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4 Answers

 By PEMDAS rule, you need to caculate inside first to get 7*8 = 56, then take square, and divide the result by 10 at the end.

[(7*8)^2] / 10 = 56^2 / 10 = 313.6

If 313.6 is not the right answer, then the original expression must be different.

For example, (7*8)^(2/10) = 2.237

 

The correctness of this answer really hinges on whether the exponent is 2 or 2/10. 

It's difficult to type these problems ... so much easier to hand write them! If you add some parentheses we'd know for certain:

((7*8)^2)/10  

or

(7*8)^(2/10)

Antoinette, from the way you've typed in the expression, it looks like the exponent is two tenths (one-fifth).  So, it's not a whole number – in fact it's less than one.  When the exponent in an expression is less than 1, the result will always be smaller than the base you started with (in this case, 56).  

Using your scientific calculator, enter 56 as the base and 0.2 as the exponent.  You'll find the result is a very long decimal approximately equal to 2.24!

Hi Antoinette! First, let's simplify the numerator to see what we have there. Remember that "order of operations" or "PEMDAS" are important here. "PEMDAS" require you to perform certain operations before others. This means you do(P)arentheses first, followed by (E)xponents, then (M)ultiplication and (D)ivision, and lastly (A)ddition and (S)ubtraction. The original problem is: (7*8)^2/10 Simplify what's inside the (P)arentheses first: (56)^2/10. Next, do the (E)xponent: 56^2 = 3136, leaving 3136/10. To divide any number by 10, simply move the decimal point one position to the left: 3136.0 becomes 313.60 This answer is already in decimal form! You're done! The answer 313.6 is correct! Remember, always obey"PEMDAS!" Hope this helped! Doug