Answer:
#1. -6/7
#2. -3.2
Explanation:
#1. (-2/7) + (-4/7)
You are adding two negative numbers.
When you add two positive numbers or two negative numbers, just ignore the signs and add the numbers as positive numbers. Then the answer has the same sign as the original numbers.
Step 1. Ignore the signs and make both numbers positive.
Add 2/7 and 4/7.
2/7 + 4/7 = 6/7
Step 2. Since the two numbers are originally negative, the answer is negative.
(-2/7) + (-4/7) = -6/7
#2. 5.4 + (-8.6)
When you add a positive number and a negative number, first make both numbers positive. Then, subtract the smaller positive number from the larger positive number. Finally, the answer has the same sign as the original number that corresponds to the larger positive number.
Here we do it step by step.
5.4 + (-8.6)
Step 1. Make both numbers positive. The numbers now are:
5.4 and 8.6
Step 2. Subtract the smaller positive number from the larger positive number.
8.6 - 5.4 = 3.2
Now look at the two positive numbers. 5.4 and 8.6. The larger number is 8.6. The original number that 8.6 came from is -8.6, a negative number, so the answer is negative.
5.4 + (-8.6) = -3.2