These are decimal numbers, and dots above some of the digits make them recurring decimals. One dot means the digit under it repeats infinitely. In other words, it goes on forever (and ever and ever).

Multiply the numbers as you would with whole numbers. Start from the right-most digit of the bottom number and multiply it by each digit in the top number. Write down individual products for each step ...

こんにちは！「100日後にそろばん完全マスター！」の主です。 Youtube72日目の動画「 そろばん3級 小数点の入ったかけ算のやり方 基本B（桁を数えるver.）」の内容を簡単に解説します。 3級は上級になり、かけ算と割り算に小数点が入った計算が出てきます。