Respuesta :

U have to jsut multiply sttiaght across
nerdsrule
Multiply straight across. For number 4 it would be 20/42 so you'd find the gcf which is 2 and you divide 20 and 42 by 2. 42 divided by 2 is 21 and 20 divided by 2 is 10. so number 4 is 10/21. 
Do the steps I did and you'll figure out the rest.