I know I line up the decimals when I add and subtract. Do I need to line the decimals up when I multiply and divide?
no you don't need to. For the multiplication. if there is a decimal in the divisor, then you need to slide the decimal to the right until it is a integar. Same done with the dividend. if there is no decimal in the divisor, and there is a decimal in the dividend, then you need to bring the decimal straight up when you are dividing.