(a) We have to find the missing space:

Let the missing space be x

Therefore,

- x =

x = –

=

=

=

(b) We have to find the missing space:

Let the missing space be x

Therefore,

x – =

x = +

=

=

(c) We have to find the missing space:

Let the missing space be x

Therefore,

x – =

x = +

=

= 1

(d) We have to find the missing space:

Let the missing space be x

Therefore,

x + =

x = –

=

=