Aman with type a blood marries a woman with type ab blood. according to predicted outcomes based on genetics, their children may have all blood types except type

Well,

We need to make a Punnett square.  Assuming that the man has type A, not AO or AA blood, we will have a 1 x 2 Punnett square.  We just have to take the A on the left and pair it with either the A on the left column or the B on the right column.

Therefore, the percent chance of having an AA genotype is 1 in 2 or 50%, while the percent chance of having an AB genotype is 1 in 2 or 50%.  Thus, the possible phenotypes are 50% A type blood and 50% AB type blood.

I have attached the resulting Punnett square.

Lacking something of the ozone layer