passing parameters on change event in angular 2

try with template reference variable

<select (change)="handle(selectField.value);" #selectField>

Try to use this approach:

HTML TEMPLATE

<select [(ngModel)]="selectedValue" (change)="handle();">
 <option [ngValue]="0">Addition</option>
 <option [ngValue]="1">Subtraction</option>
 <option [ngValue]="2">Multiplication</option>
 <option [ngValue]="3">Division</option>
</select>

HomeComponent COMPONENT

import {Component,OnInit} from '@angular/core';

@Component({
    selector: 'app-home',
    templateUrl: './home.component.html',
    styleUrls: ['./home.component.css']
})
export class HomeComponent implements OnInit {
    selectedValue: number;
    n1 = 0;
    n2 = 0;
    result = 0;

    handle() {
        alert("selected option's value is " + this.selectedValue);
    }

    constructor() {}
    ngOnInit() {

    }
}

Consider also

<select (change)="handle($event.target.value);">