Posted by Tessa on Sunday, March 15, 2009 at 7:58pm.
I worked this in two different orders to make sure I was right.
8-(-2/3)+7-(1 2/3)+5=
8 + 2/3 + 7 - 1 2/3 + 5 =
15 + 5 - 1 = 19
8 2/3 + 5 1/3 + 5 = 19
Ok, I'll do the 1st one;
first of all 8 - (-2/3)
well, minus times minus = plus
[e.g. -4*-4 = 16]
so that becomes 8 + 2/3
Now we need to do the same with the rest of the equation to get
8 + 2/3 + 7 - 1 2/3 + 5
You how have to sort out 1 2/3 which is 1 and 2/3 which equals 5/3
So now we have 8 + 2/3 + 7 - 5/3 + 5
Now we add the fractions together and the whole numbers together separately to get
(8 + 7 + 5) + (2/3 - 5/3)
which becomes
(20) + (-3/3)
which becomes
20 - 1 = 19
So 19 is the answer.
I hope that helps
you have to remember that when you subtract a negative, you really add it - the () were used in your problems to section off numbers
8-(-2/3) would be the same as 8 + 2/3
just in case you're still stuck on the 2nd & 3rd ones - one more thing to remember: when you add/subtract fractions, they need common denominators
#2) (-3)-2.2-9-(-12)=
(-3) - 2.2 = -5.2 - 9 - (-12)
-5.2 -9 = -14.2 -(-12)
*remember the -(-12) is really adding
-14.2 + 12 = -2.2
#3) - this one needs common demoninators
-2/7-2 3/5+1 2/7-(-2/5)=
-2/7 will become -10/35
2 3/5 will become 2 21/35
1 2/7 will become 1 10/35
-10/35 - 2 21/35 = -2 31/35
-2 31/35 + 1 10/35 is really subtracting and keeping the sign from the higher number (negative here)
= -1 21/35 -(-2/5) *you'll need to have common denominators here too - it might be easier to go back to the 5ths
-1 21/35 becomes -1 3/5
-1 3/5 - (-2/5) =
-1 3/5 + 2/5 =
-1 1/5 is your answer