19) 2 + 6 + (−7) + 10 20) (−5) + (−8) + (−2) + 1 21) (−6.8) + (−1.9) 22) 2.489 + (−4.3) 23) (−4.7) + 5.7 24) (−5) + (−7.1) 25) (−3.9) + 7.1

I'll do the first two for you to show you how to do it, then have you try the other ones.

19) 2 + 6 + (−7) + 10

Start from the left and work our way right, becuase these are all addition and subtraction. If we multiplication, division, exponets or something like that we would do those first.

2 + 6 + (−7) + 10

8 + (-7) + 10

Now we have 8 + (-7). We don't really need this positive sign, so we get 8 - 7. The rule here is that adding a negative is the same thing as subtracting a poisitve.

8 + (-7) + 10

8 -7 + 10

1 + 10

11

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20) (−5) + (−8) + (−2) + 1

Again, just addition and subtraction so we work our way from the left to the right.

(−5) + (−8) + (−2) + 1

Again, we are adding a negative. Like I said in the last problem, this is really like subtracting a positive.

(−5) + (−8) + (−2) + 1

(−5) −8 + (−2) + 1

Right now we "owe" -5. Then we loose another 8. We end up with -13.

(-13) + (−2) + 1

(-13) −2 + 1

(-15) + 1

Now we "owe" -15, and we get one. We now don't owe as much, we only owe -14.

(-14)

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Let me know if you need help with the others, but don't just say "I can't do the other ones." Tell me what you don't understand and I can then help you out.