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Which expression has an estimated product of [tex]$45$[/tex]?

A. [tex]$44.7 \times 2.1$[/tex]

B. [tex]$7.5 \times 8.4$[/tex]

C. [tex]$8.7 \times 5.28$[/tex]

D. [tex]$38.1 \times 7.3$[/tex]

Answer :

We are asked to determine which expression has an estimated product of [tex]$45$[/tex]. The idea is to round each factor to the nearest whole number, multiply the rounded numbers, and compare the resulting estimated products with [tex]$45$[/tex]. Let's go through each expression step by step.

1. For the expression
[tex]$$44.7 \times 2.1,$$[/tex]
round the numbers:
- [tex]$44.7$[/tex] rounds to [tex]$45$[/tex],
- [tex]$2.1$[/tex] rounds to [tex]$2$[/tex].

Then, the estimated product is
[tex]$$45 \times 2 = 90.$$[/tex]

2. For the expression
[tex]$$7.5 \times 8.4,$$[/tex]
round the numbers:
- [tex]$7.5$[/tex] rounds to [tex]$8$[/tex],
- [tex]$8.4$[/tex] rounds to [tex]$8$[/tex].

Thus, the estimated product is
[tex]$$8 \times 8 = 64.$$[/tex]

3. For the expression
[tex]$$8.7 \times 5.28,$$[/tex]
round the numbers:
- [tex]$8.7$[/tex] rounds to [tex]$9$[/tex],
- [tex]$5.28$[/tex] rounds to [tex]$5$[/tex].

Therefore, the estimated product is
[tex]$$9 \times 5 = 45.$$[/tex]

4. For the expression
[tex]$$38.1 \times 7.3,$$[/tex]
round the numbers:
- [tex]$38.1$[/tex] rounds to [tex]$38$[/tex],
- [tex]$7.3$[/tex] rounds to [tex]$7$[/tex].

So, the estimated product is
[tex]$$38 \times 7 = 266.$$[/tex]

Among the four options, the expression [tex]$$8.7 \times 5.28$$[/tex] gives an estimated product of [tex]$45$[/tex].

Thus, the correct answer is the third option.

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