Question

1-2+3-4+...+45-46+47=?​

Answer 1

До 46 включительно имеем 23 пары ,каждая из которых равна

-1

1-2=-1

3-4=-1

5-6=-1 итд

23* (-1)+47= 24

Answer 2

To find the value of the expression 1-2+3-4+...+45-46+47, we need to follow the pattern of alternating addition and subtraction.

Let's group the terms in pairs:

(1-2) + (3-4) + ... + (45-46) + 47

Now, observe that each pair (a-b) simplifies to (a-b) = a + (-b). So, the expression becomes:

(1 + (-2)) + (3 + (-4)) + ... + (45 + (-46)) + 47

Now, the numbers in each pair will cancel each other out, except for the last number 47, which will remain unchanged.

The expression now becomes:

(-1) + (-1) + ... + (-1) + 47

Since there are 45 pairs of (-1), we can represent them as -1 repeated 45 times:

-1 * 45 + 47

Now, calculate the value:

-45 + 47 = 2

So, the value of the expression 1-2+3-4+...+45-46+47 is 2.