b) in b the number of blocks are 4 and the shaded ones are 2 so the fraction is:
[tex]\frac{2}{4}=\frac{1}{4}+\frac{1}{4}[/tex]and the diagram will be:
c) in this case the total number of blocks are 5 and the sahded ones are 3, but they are grouped like:
[tex]\frac{3}{5}=\frac{1}{5}+\frac{2}{5}[/tex]and the diagram will be:
d) in this case we have 6 blocks and 5 shaded and they are grouped like this so:
[tex]\frac{5}{6}=\frac{3}{6}+\frac{2}{6}[/tex]and the diagram will be: