# 2. Clone 1

The teacher wanted to write an example for calculation on the board:

$$
1,05+1,15+1,25+1,4+1,5+1,6+1,75+1,85+1,95=?
$$

but accidentally forgot to write one comma. After this, Kolya went to the board and, correctly performing all the operations, obtained an integer result. What is it?
Answer: 27

## Solution

Let's calculate the sum

$$
1.05+1.15+1.25+1.4+1.5+1.6+1.75+1.85+1.95=13.5
$$

Therefore, in order to get an integer, the decimal point should be omitted in the number with the fractional part 0.5. As a result, instead of the number 1.5, the number 15 will appear on the board, and the result will increase by $15-1.5=13.5$ and will be equal to 27. We can also calculate it differently: notice that $1.05+1.95=1.15+1.85=1.25+1.75=1.6+1.4=3$. Then Kolya got the sum $3 \cdot 4+15=27$.

## Clone 2

The teacher wanted to write on the board the following calculation:

$$
2.05+2.15+2.25+2.4+2.5+2.6+2.75+2.85+2.95=?,
$$

but accidentally forgot to write one decimal point. After this, Kolya went to the board and, correctly performing all the operations, got an integer result. What is it?

## Answer: 45

## Clone 3

The teacher wanted to write on the board the following calculation:

$$
3.05+3.15+3.25+3.4+3.5+3.6+3.75+3.85+3.95=?,
$$

but accidentally forgot to write one decimal point. After this, Kolya went to the board and, correctly performing all the operations, got an integer result. What is it?

## Answer: 63

## Clone 4

The teacher wanted to write on the board the following calculation:

$$
4.05+4.15+4.25+4.4+4.5+4.6+4.75+4.85+4.95=?,
$$

but accidentally forgot to write one decimal point. After this, Kolya went to the board and, correctly performing all the operations, got an integer result. What is it?

## Answer: 81