Consider the following spreadsheet:

What formula would you use to calculate the number in cell B2?

Cell A Cell B Cell C

Cost of item 4% tax cost of
before tax item with
tax
$130 5.2 $135.2
$150 6 $156

I do not know how to write a formula for calculate cell B.

To calculate the number in cell B2, you would use the formula =A2*(B1/100). Here's an explanation of how this formula works:

1. In cell B1, you have the label "4% tax", which represents the tax rate as a percentage.
2. In cell A2, you have the cost of the item before tax, which is $130.
3. To calculate the tax amount, you need to multiply the cost of the item by the tax rate. This is done by dividing the tax rate in cell B1 by 100, to convert it from a percentage to a decimal.
4. The formula =A2*(B1/100) means multiplying the value in cell A2 by (B1/100) to get the tax amount.
5. In the case of cell B2, it would be =A2*(B1/100) which equals $130 * (4/100) = $130 * 0.04 = $5.2.

So, the formula calculates the tax amount for the cost of the item in cell A2, using the tax rate in cell B1, and gives you the result in cell B2.