Changing numbes in text fields into numbers in number fields

I have a list of numbers that are in text field. I need to make calculations with them. So I change the field value "text" into "number". It still won't work. I try to copy and paste special those fields and still no good. I have wasted way too much time on this.
Any thoughts?

There is no need to change the format as long as the " numbers " are involved in operations like + - etc
If you use them otherwise ( fi comparison) just add 0 to the "number"

As you found out, changing the format of text formatted values doesn't work. Try either of these:

Select column of "text numbers"

data > text to columns > finish

That should convert them

Alternatively....copy a single empty cell, select column of "text numbers" and use

Edit > Paste Special > under "Operation" select "Add" and hit OK

Thank you very much.
I used the multiply with one option and it worked...
But I appreciate the help from you all guys.