Lightning - How to read input values based on ids

How to read input values based on ids.txt

If we want read the input values by using ids we need to use 
component.find("Id of the element").get("v.value"); 
If we want to set any value based on id we need to use below code
component.find("Id of the element").set("v.value"); 

Component: 
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<aura:component >
	<lightning:card iconName="standard:contact">
    	<aura:set attribute="actions">
        	<lightning:buttonGroup>
                <lightning:button label="Add" aura:id="add" name="Addition" onclick="{!c.calculate}" />
                <lightning:button label="Mul" aura:id="mul" name="Mutilication" onclick="{!c.calculate}" />
                <lightning:button label="Cancel" aura:id="cancel" name="Cancel" onclick="{!c.calculate}" />
            </lightning:buttonGroup>
        </aura:set>
        <aura:set attribute="title">
            Calculator<br/>
            Simple Calculator
        </aura:set>
        <lightning:input label="Enter A Value: " aura:id="aval" name="Avalue" required="true" /> 
        <lightning:input label="Enter B Value: " aura:id="bval" name="Bvalue" required="true" />
        <lightning:input label="Result " aura:id="result" name="Result"/>
    </lightning:card>
</aura:component>
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Controller
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({
	calculate : function(component, event, helper) {
        var evt = event.getSource(); // From which element event was occured ? 
        var id = evt.getLocalId(); // Id of the element from which event occured
        var name = evt.get("v.name"); // Name of the element from which event occured
        var a = component.find("aval").get("v.value"); // Getting the value from the input component based on id "aval"
        var b = component.find("bval").get("v.value"); // Getting the value from the input component based on id "bval"
        if(id=='add'){
            console.log(id);
            var result=parseInt(a)+parseInt(b);
            component.find("result").set("v.value",result); // Setting  the value to the input component based on id "result"
        }else if(id=='mul'){
            console.log(id);
            var result=a*b;
            component.find("result").set("v.value",result);
        }else{
            console.log(id);
            component.find("aval").set("v.value",null);
            component.find("bval").set("v.value",null);
            component.find("result").set("v.value",null);
        }
		
	}
})
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