2/10 are shaded, this therefore means that if u times it by 10 it will give you the percentage, so 10x10 is 100 and 2x10=20 so it is 20/100 so the percentage is 20% as all percentages are out of 100%. The fraction is 2/10 which can be simplified down to 1/5 if u divide it by 2. The decimal is 0.2 because you divide when u divide 2 by 10 it gives u 0.2
