100 billion seconds minus 100 million seconds is approximately equal to

100 billion seconds minus 100 million seconds is approximately equal to

a. 100 billion seconds

b. 99 billion seconds

c. 10 billion seconds

d. 1 billion seconds

The correct answer and explanation is :

The correct answer is b. 99 billion seconds.

Let’s break down the math behind this:

1. Understanding the values:

• 100 billion seconds = 100,000,000,000 seconds
• 100 million seconds = 100,000,000 seconds

1. Subtraction:
   To find 100 billion seconds minus 100 million seconds, we subtract the smaller value from the larger value: [
   100,000,000,000 \, \text{seconds} – 100,000,000 \, \text{seconds} = 99,900,000,000 \, \text{seconds}
   ]
2. Approximation:
   The result, 99,900,000,000 seconds, is very close to 99 billion seconds. In fact, it’s only 100 million seconds less than 100 billion seconds. Since we are asked to find an approximate value, we round 99,900,000,000 to 99 billion seconds. This approximation works because the difference between 100 billion and 99,900,000,000 is quite small, and when dealing with large numbers like these, it’s common to round to the nearest significant figure (in this case, billions).
3. Comparison with other choices:

• a. 100 billion seconds is incorrect because the subtraction does reduce the value slightly (by 100 million seconds).
• c. 10 billion seconds is too far off and not close to the result of the subtraction.
• d. 1 billion seconds is also incorrect, as the difference is much smaller than this.

Therefore, the correct choice is b. 99 billion seconds, as it’s the closest and most accurate approximation to the result of subtracting 100 million seconds from 100 billion seconds.