Could I change this to "half"? Yes.
Could I write "fifty percent", not using numbers, but with letters?
Yes, I could spell out "fifty percent", it's all the same; it means the same thing.
There is, however, one thing you should be aware of.
In English, we do not like to start sentences with numbers.
So, for example: "50% of the living expenses is rent.", this is...this is not good, we don't like to start out with a number.
比如："50% of the living expenses is rent."（50%的生活费花在了房租上），这......这不好，我们不喜欢用阿拉伯数字开头。
It would be better to actually write it out. Okay? Just like that, okay, excellent.
So, again, these are great sentences to use when you're writing about pie charts.
So, now let's look at some ways to talk about numbers.
We've already talked about 50%, we've talked about how it can be called half, and how...the different spellings of 50%.
So, now, let's look at some other different ways to talk about percents.
I have down here the word "a third",
so, if this is my pie chart, a third, there are three pieces, would be about this, which is around 30 to 35 percent is a third. Okay?
I can also talk about "a quarter", which would be about 25%.
Okay? If we looked up here, food is about a quarter.
We can also talk about "two thirds", this is where it gets a little bit confusing.
So, a third is, like I said, we have one out of three, here we have two out of three, which is about 66%, so, two thirds would look like...one third, two thirds.
"a third"，就像我说过的，是三份中的一份，这里我们有三份中的两份，也就是66%左右，所以"two thirds"看上去就是......这是"one third", 这是"two thirds"。
Okay? So, this is one third and this is two thirds.
所以这是"one third"，而这是"two thirds"。