Caitlin has 4 3/4 pounds of clay . she uses 1 1/10 pounds to make a cup ,and another 2 pounds to make a jar , how many pounds are left
write an equation

There are 33/20 or 1.65 pounds left.

Given:
4 3/4 pounds of clay
1 1/10 pounds of clay for a cup
2   pounds of clay for a jar

Convert the mixed fraction into fractions.
4 3/4 = (4*4+3)/4 = 19/4
1 1/10 = (1*10+1)/10 = 11/10
2 = 2/1

19/4 - 11/10 = (19/4 *5/5) - (11/10 * 2/2) = 95/20 - 22/20
= (95-22)/20 = 73/20 or 3.65 pounds after making a cup  

73/20 - 2/1 = 73/20 - (2/1 * 20/20) = 73/20 - 40/20 = 73 - 40 / 20 = 33/20  OR 1.65 pounds left after making a jar.

We can also convert the fractions into decimal numbers.
19/4   = 4.75
11/10 = 1.10
2/1     = 2.00

4.75 - 1.1 - 2 = 1.65 pounds left.