please help asap

If there are 25 students in a class. On an exam 4 got the grade 7 or higher both in math and chemistry. Three more got the grade 7 or higher in chemistry than in math and eight for lower than 7 in both math and chemistry. How many kids got a 7 or higher in math?

Draw a venn diagram and form an equation

Can anyone explain to me how I can get the answer? I’ve been stuck at this for some time