Answer: integral

AnswerCrossword Clue
INTEGRAL

Mandatory

INTEGRAL

Necessary

INTEGRAL

Calculus computation

INTEGRAL
Indispensible
INTEGRAL
Vital
INTEGRALComplete.
INTEGRALEssential to completeness.
INTEGRALEssential.
INTEGRALBranch of calculus
INTEGRALComplete
INTEGRALBasic
INTEGRALUnlike 1-2
INTEGRALAbsolutely necessary
INTEGRALNecessary, as a part
INTEGRALCrucial