Answer:
you should always line up the number, but the decimal point or you could also think as if the decimal number is just number and it doesn't have point.
ex : 4.56 = 456
now multiply each numbers from left to right and you should not care about a decimal point
ex: (4.56 times 55.5) or could think that are no decimal points, like (456 times 555)
now then you add the products and now you could care about the decimal point.
