How confident are you that you can subtract numbers down your page, using a vertical algorithm?
Find the value of $54-32$54−32.
Another word that we can use to describe the ones place is 'units'.
You might notice that sometimes the standard algorithm is called the 'vertical algorithm'. Let's think about why. When we use the standard algorithm, we line our numbers up in 'vertical' place value columns.
Let's see what we need to do when we don't have enough in one of our place value columns to subtract.
Find the value of $73-15$73−15.
We always start from the ones place, when we work down our page. If we don't have enough ones to subtract, we need to trade from the tens place.