Answer:
The best estimate for the value of the given expression is -2 1/2. Correct: Second alternative
Explanation:
Estimate and Number Rounding
There are situations where numbers must be estimated according to certain rules. If we have a number and we need a good approximate to it, we can use rounding to the required number of decimals.
The question requires to find the best estimate for the operation:
[tex]\displaystyle \left(\frac{34}{8}-\frac{16}{3}\right)-\frac{14}{9}[/tex]
We calculate the decimal value of the expression:
[tex]\displaystyle \left(\frac{34}{8}-\frac{16}{3}\right)-\frac{14}{9}=(4.25-5.33)-1.56=-2.64[/tex]
The first alternative is incorrect. It's a good approximation because it's close to the number, but the next alternative is the closest of all choices.
The second alternative Is correct. The value of -2 1/2 is -2.5. The number -2.64 is closer to -2.5 than to -3 which is the alternative A.
The third alternative Is incorrect. 7 is a positive number and it's not even close to -2.64
The last alternative Is incorrect. 7 1/2 = 7.5 is a positive number and it's not even close to -2.64
