After a lot of adding whole numbers, we will learn to add decimal numbers and we will see that we do this frequently in our daily lives, without even realizing it. It will be easy, easy, you will see!
Do you still remember that the number system is a system based on number 10, Is not it? We see this when we add 10 units, and these 10 units can be called 1 ten. When we do this with decimal numbers, it's no different. Give a reminder, looking at the article from Decimal numbers, so you will better understand how to add these numbers.
The addition rules for real numbers still hold for decimals, but now we will have numbers with commas; and after those commas, our decimal numbers. Let's think about the following situation:
Pedro and his friend Jean want to buy a cookie for a snack. When they observed the price of the biscuit at the supermarket, they saw that it cost BRL 2.00. Pedro told his friend Jean “We won't be able to buy this cookie, as I only have R$1.50”.
Then Jean said: “Don't worry, we'll be able to buy the biscuit as I have fifty cents!
Do you think Jean is right that they will be able to buy the cookie? Because?
To know if they will be able to buy it, we need to know how much of money Pedro and Jean have together, i.e, we need to add the money of both.
So we have to add one more unit in the unit house, because, with 10 tenths, we completed 1 unit.
That is, the friends together have BRL 2.00 reais, and with that they will be able to buy the package of biscuits they want so much.
It saw? there's no secret, just arrange the numbers so that you are adding the correct places. Unit with unit, tenth with tenth, and so on.
Get your friends together and add up the coins you have and see how much money you have!
By Gabriel Alessandro de Oliveira
Graduated in Mathematics
Take the opportunity to check out our video lesson on the subject:
