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 mustn't subtract
you mustn't subtract
she mustn't subtract
we mustn't subtract
you mustn't subtract
they mustn't subtract 	I mustn't be subtracting
you mustn't be subtracting
she mustn't be subtracting
we mustn't be subtracting
you mustn't be subtracting
they mustn't be subtracting	I mustn't have subtracted
you mustn't have subtracted
she mustn't have subtracted
we mustn't have subtracted
you mustn't have subtracted
they mustn't have subtracted	I mustn't have been subtracting
you mustn't have been subtracting
she mustn't have been subtracting
we mustn't have been subtracting
you mustn't have been subtracting
they mustn't 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 	
mustn't I subtract?
mustn't you subtract?
mustn't she subtract?
mustn't we subtract?
mustn't you subtract?
mustn't they subtract? 	mustn't I be subtracting?
mustn't you be subtracting?
mustn't she be subtracting?
mustn't we be subtracting?
mustn't you be subtracting?
mustn't they be subtracting? 	mustn't I have subtracted?
mustn't you have subtracted?
mustn't she have subtracted?
mustn't we have subtracted?
mustn't you have subtracted?
mustn't they have subtracted? 	mustn't I have been subtracting?
mustn't you have been subtracting?
mustn't she have been subtracting?
mustn't we have been subtracting?
mustn't you have been subtracting?
mustn't they have been subtracting?