As we know, a decimal consists of a whole part and a fractional part. When adding decimals, the whole and fractional parts are added separately.

For example, let's add the decimals 3.2 and 5.3. It is more convenient to add decimals in columns.

Let's first write these two fractions in a column, making sure the whole parts are under the whole parts and the fractional parts are under the fractional parts. At school, this requirement is called "dot under dot".

Let's write the fractions in a column so that the decimal point is under the point:


Add up the fractional parts: 2 + 3 = 5. Write five in the fractional part of our answer:


Now add the whole parts: 3 + 5 = 8. Write the eight in the whole part of our answer:


Now separate the whole part from the fractional part with a dot. To do this, again follow the rule "dot under dot":


The answer is 8.5. So the expression 3.2 + 5.3 equals 8.5

3.2 + 5.3 = 8.5

In fact, not everything is as simple as it seems at first glance. Here, too, there are pitfalls, which we are now going to talk about.


Task 1. Perform addition:
0.6 + 0.3
Task 2. Perform addition:
1.2 + 5.3
Task 3. Perform addition:
1.6 + 0.4
Task 4. Perform addition:
0.8 + 0.5

Video lesson

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