Calculate the number of cubes in one group and the other. Add up two numbers. Write down the equation if you need to.

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How can we represent the number 36 using objects? We can draw 36 shapes randomly arranged in space.

In this case, only we will know their number. Others will need to count them again.

We can use the knowledge of tens and ones in two-digit numbers.

Number 36 consists of 3 tens and 6 ones. Let’s group these shapes by 10s. There will be 3 groups, and 6 cubes will be left.

The number 3 denotes the number of tens, which is in the first place on the left. The number 6 shows the number of ones and is first on the right.

Also, we can use objects to add up the numbers. Let’s add up two groups of cubes.

First, we will denote the number of objects in each group.

We can see, the blue cubes are combined into 3 sets with 10 objects in each, and 5 more cubes are left. It is number 35. Green cubes are arranged in 4 groups with 10 items in each, and 4 single cubes are left. We denote it as number 44.

Let’s combine blue and green cubes in one group. We will add 4 sets of green cubes to 3 sets of blue. Also, we will group 5 blue and 4 green cubes.
 

We get 7 groups of cubes with 10 objects in each and 9 separate cubes beside. It is number 79, which consists of 7 tens and 9 ones.

Thus, 35+44=79.

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