Compute

Type each number as a decimal (like 4.25). Dollar signs and commas are fine.

Why the steps work

Adding / subtracting: the decimal point is the anchor — lining it up forces tenths to add to tenths and hundredths to hundredths. The point in the answer drops straight down.

Multiplying: the whole-number product counts every tiny piece; the total decimal places tell you how small each piece is, which is exactly where the point goes.

Dividing: sliding both points the same distance multiplies top and bottom by the same power of 10 — the value never changes, but the divisor becomes a friendly whole number.