ERROR error: _co.computeCALCULATE is not a function

Completely new beginner here, im kind of lost to why this wont work. i need help

home.html
<button ion-button color=“primary” (click)=“computeCALCULATE ()”>CALCULATE

home.ts
computeCALULATE() {

this.UnitPrice_A = (this.Cost_A/this.Volume_M)*1000;

this.UnitPrice_B = this.Cost_B/this.Volume_L;

this.Savings = this.UnitPrice_B - this.UnitPrice_A;

}

}