Question

Which shows the expression below simplified? 0.00048 - (3.4 × 10-5) A. 4.46 × 10-4 B. 3.39952 × 10-5 C. 4.46 × 10-5 D. 1.4 × 10-4

Answer 1

Option C

The simplified form of given expression is $4.46 \times 10^{-4}$

Solution:

Given that we have to simplify the expression shown below

$0.00048 - (3.4 \times 10^{-5})$

Let us first convert 0.00048 to scientific notation

Steps to follow:

Move the decimal point in your number until there is only one non-zero digit to the left of the decimal point. The resulting decimal number is a.

Count how many places you moved the decimal point. This number is b.

If you moved the decimal to the left b is positive.

If you moved the decimal to the right b is negative.

If you did not need to move the decimal b = 0.

Write your scientific notation number as a x 10^b and read it as "a times 10 to the power of b."

Remove trailing 0's only if they were originally to the left of the decimal point.

$0.00048 = 4.8 \times 10^{-4}$

So the given expression becomes,

$\rightarrow 4.8 \times 10^{-4} - 3.4 \times 10^{-5}$

Let us make the exponent of second term as -4

$\rightarrow 4.8 \times 10^{-4} - 0.34 \times 10^{-4}$

Take $10^{-4}$ as common term,

$\rightarrow 10^{-4} (4.8 - 0.34)$

$\rightarrow 4.46 \times 10^{-4}$

Thus option C is correct