JSFiddle - React, Tailwind, and code Playground

HTML

<div ng-app='app'>
<div ng-controller='ctrl'>
    <input type="number" ng-model="samount" ng-change="getSR(samount)"/>
    <input type="number" ng-model="ramount" ng-change="getRS(ramount)"/>
</div>
</div>

JavaScript

angular.module('app',[])
.controller('ctrl',function( $scope ){
    $scope.getSR = function(amount) {
        console.log('getSR()');
        $scope.ramount = parseFloat((amount*5.25).toFixed(3));
    };
    
    $scope.getRS = function(amount) {
        console.log('getRS()');
        $scope.samount = parseFloat((amount/5.25).toFixed(3)); 
        
    };
});