I am confused.
Do you need 10 x 10 squares?
Or do you need 7x7 squares cut from 10x10 squares?
Did you wash your fabrics yet? After washing and drying, one can see that some fabrics were not cut on the crosswise grain.
Whichever - I would tear the needed width plus one inch from each of the fabrics (If I needed 7x7 squares, I would measure 8 inches from the end and tear). Then I would press (and starch/size - if that's what you do) each of the widths and cut from those wide strips.
If I was in serious OCD mode, I would pull a thread to straighten the ends and then cut along that line.
But if I have "plenty" of fabric, I would probably tear the needed amount off the longer lengths. I do like to leave a bit "extra" for the first tear - sometimes the fabric is cut way off grain - tearing also causes some trauma to the torn edges - sometimes only 1/4 inch or so - sometimes up to an inch.
I'm not THAT into ironing/pressing!!