Keyboard is typing random numbers when letters are pressed?

My keyboard's "asdfghjkl" line of letters, when pressed, type a number unintentionally. When I press "a", it types a1, and when I type "s", it types s2, and so on. Sometimes, the problem doesn't occur, and it types normally. But then, the problem comes back. The number row types letters after I type numbers as well. How do I fix this? Do I need to replace the keyboard? Or is there another way?

That was typed on my PC. Here's the same thing, typed on my Macbook. I copied the following text and put in in iCloud notes, and then copied it from iCloud notes to this website using my PC. You can clearly see the problem.

My keyboar1d3’s2 “a1s2d3f4g5h6j7k8l9” l9ine of4 l9etters2, wh6en pres2s2ed3, type a1 number unintentiona1l9l9y. Wh6en I pres2s2 “a1” it types2 a1a1, a1nd3 wh6en I type “s” it types2 s2s2, a1nd3 s2o on. how do i fix this? do i need to replace the keyboard? or is there another way?