These are a pair of my youngest child’s pants that he has worn a big hole in the knee.
I used a scrap price of fabric to place on the inside of the pants, behind the hole. Then I pinned it in place before using a zig zag stitch to darn the pieces together.
Not only is the hole ‘filled in’ with the extra fabric, but it is also reinforced with the zig zag stitch.
As quickly as children grow, he may only fit these for another 6 months or so, but at least they’ll last the whole time