Which expression best estimates [tex]-18 \frac{1}{4} \div 2 \frac{2}{3}[/tex]?

A. [tex]18 \div 3[/tex]

B. [tex]-18 \div 3[/tex]

C. [tex]-18 \div (-3)[/tex]

D. [tex]18 \div (-3)[/tex]



Answer :

To find the expression that best estimates \(-18 \frac{1}{4} \div 2 \frac{2}{3}\), let's go through the problem step-by-step.

### Step 1: Convert Mixed Numbers to Improper Fractions
First, we need to convert the mixed numbers \(-18 \frac{1}{4}\) and \(2 \frac{2}{3}\) into improper fractions.

1. \(-18 \frac{1}{4}\):
[tex]\[ -18 \frac{1}{4} = -18 - \frac{1}{4} = -18.25 \][/tex]

2. \(2 \frac{2}{3}\):
[tex]\[ 2 \frac{2}{3} = 2 + \frac{2}{3} = 2.6667 \, (\text{approximately}) \][/tex]

### Step 2: Perform the Division
Now, we perform the division of these two numbers:
[tex]\[ \frac{-18.25}{2.6667} \approx -6.84375 \][/tex]

### Step 3: Identify the Closest Fraction from Choices
We compare the computed value with the given choices:

1. \(18 \div 3\):
[tex]\[ 18 \div 3 = 6.0 \][/tex]

2. \(-18 \div 3\):
[tex]\[ -18 \div 3 = -6.0 \][/tex]

3. \(-18 \div (-3)\):
[tex]\[ -18 \div (-3) = 6.0 \][/tex]

4. \(18 \div (-3)\):
[tex]\[ 18 \div (-3) = -6.0 \][/tex]

### Step 4: Find the Closest Estimate
Now, we determine which one of the results above is closest to \(-6.84375\). We compare the absolute differences:

- Difference from \(6.0\):
[tex]\[ |6.0 - (-6.84375)| = 12.84375 \][/tex]

- Difference from \(-6.0\):
[tex]\[ |-6.0 - (-6.84375)| = 0.84375 \][/tex]

Since \(|-6.0 - (-6.84375)| = 0.84375\) is the smallest difference, the choice \(-18 \div 3 = -6.0\) is the closest estimate.

Thus, the best estimate for the expression \(-18 \frac{1}{4} \div 2 \frac{2}{3}\) is:
[tex]\[ 18 \div (-3) = -6.0 \][/tex]

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