must subtract
Regular verb: subtract - subtracted- subtracted

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must subtract
you must subtract
she must subtract
we must subtract
you must subtract
they must subtract 	I must be subtracting
you must be subtracting
she must be subtracting
we must be subtracting
you must be subtracting
they must be subtracting	I must have subtracted
you must have subtracted
she must have subtracted
we must have subtracted
you must have subtracted
they must have subtracted	I must have been subtracting
you must have been subtracting
she must have been subtracting
we must have been subtracting
you must have been subtracting
they must have been subtracting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not subtract
you must not subtract
she must not subtract
we must not subtract
you must not subtract
they must not subtract 	I must not be subtracting
you must not be subtracting
she must not be subtracting
we must not be subtracting
you must not be subtracting
they must not be subtracting	I must not have subtracted
you must not have subtracted
she must not have subtracted
we must not have subtracted
you must not have subtracted
they must not have subtracted	I must not have been subtracting
you must not have been subtracting
she must not have been subtracting
we must not have been subtracting
you must not have been subtracting
they must not have been subtracting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I subtract?
must you subtract?
must she subtract?
must we subtract?
must you subtract?
must they subtract? 	must I be subtracting?
must you be subtracting?
must she be subtracting?
must we be subtracting?
must you be subtracting?
must they be subtracting? 	must I have subtracted?
must you have subtracted?
must she have subtracted?
must we have subtracted?
must you have subtracted?
must they have subtracted? 	must I have been subtracting?
must you have been subtracting?
must she have been subtracting?
must we have been subtracting?
must you have been subtracting?
must they have been subtracting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not subtract?
must you not subtract?
must she not subtract?
must we not subtract?
must you not subtract?
must they not subtract? 	must I not be subtracting?
must you not be subtracting?
must she not be subtracting?
must we not be subtracting?
must you not be subtracting?
must they not be subtracting? 	must I not have subtracted?
must you not have subtracted?
must she not have subtracted?
must we not have subtracted?
must you not have subtracted?
must they not have subtracted? 	must I not have been subtracting?
must you not have been subtracting?
must she not have been subtracting?
must we not have been subtracting?
must you not have been subtracting?
must they not have been subtracting?