Homework help with fractions and simple subtraction?

Question

Oh cool. That sorta rhymes. Okay. I have two real easy problems, but I'm tired as h*ll and I need sleep.

18 - 20 1/5

z - 3.5 for z = 1

(What is z?)

I do not just want answers. I would like the explanation for future reference. Thank you so much for your help!

Answer 1

Edit:  Okay, if I recall, math teachers want you to work in fractions throughout (though I prefer integers) so you have to convert the numbers into matching fractions by multiplying them by the divisor.  18*5=90, 20*5=100+1=101.  Now do your subtraction.  90-101=11.  Convert them back to a fraction by dividing by 5.  2 1/5 is your answer.

Edit part 2: So you're just substituting 1 for z?  Therefore you should write the expression as 1-3.5= -2.5

(sorry I initially thought you might be solving for z.)

And Tony is quite wrong, so please ignore him.

Answer 2

-2.5

-2.5

Answer 3

use www.mathway.com

Answer 4

18-20 1/5=

18= 17 5/5

     -20 1/5=

-------------------------

    - 2 4/5

z-3.5=   z=1=   1-3.5=-2.5