Calculate the formula according to the meaning of the question:

90-28-36

=90-(28+36)

=90-64

=26

So I have to make 26 more songs to finish them all.

Arithmetic operation of addition and subtraction:

Integer addition and subtraction, the same digits are aligned, starting with single digits, and when the addition reaches ten digits, the higher digits will be entered; If the subtraction is not enough, subtract 1 from the high position. When this number is added to 10, it will decrease.

Subtraction is the inverse operation of addition; Multiplication is a special form of addition; Division is the inverse operation of multiplication; Power is a simple form of multiplication; The root is the inverse operation of power.