Answer will be 90 as Middle value is the multiplication of corner values

The answer is 9*10=90. it can be understood as all the middle values are the multiplication of corner two values.

6*5=30 5*9=45 9*10=90 10*6=60

Even I have the same answer 90.

If

4+5+4+5=81 5+6+5+6=16 6+7+6+7=64 1+2+1+?=16

What is the missing number?

Look at the numbers given in the picture and find the missing number.

Find a number which is Divided by 2 the balance should be 1, div by 3 bal 2, div by 4 bal 3, div by 5 bal 4, div by 6 bal 5, div by 7 bal 0, div by 8 bal 7.