UI -
<aura:component >
    <aura:attribute name="pageNumber" type="Integer" default="1"/>
    <aura:attribute name="lastPageNumber" type="Integer"/>
    <div class="slds-button-group" role="group">
      <button class="slds-button slds-button_neutral" onclick="{!c.onButtonClick}" disabled="{!v.pageNumber == 1}">First</button>
      <button class="slds-button slds-button_neutral" onclick="{!c.onButtonClick}" disabled="{!v.pageNumber == 1}">Previous</button>
      <button class="slds-button slds-button_neutral" onclick="{!c.onButtonClick}" disabled="{!v.pageNumber == v.lastPageNumber}">Next</button>
      <lightning:button label="Last" title="Last" onclick="{! c.onButtonClick}" disabled="{!v.pageNumber == v.lastPageNumber}"/>
      <div>Page: {!v.pageNumber} of {!v.lastPageNumber}</div>

    </div>
</aura:component>

Controller -
({
	onButtonClick : function(cmp, event, helper) {
        debugger;
        //console.log('Button Name: '+event.target.innerHTML);
        var buttonType;
        if(event.getSource)
        	buttonType = event.getSource().get("v.label");
        else
            buttonType = event.target.innerHTML;
        console.log('Button Name: '+buttonType);
        if(buttonType == 'First') {
			cmp.set("v.pageNumber",1);
        }
        else if(buttonType == 'Previous') {
			cmp.set("v.pageNumber",cmp.get("v.pageNumber")-1);
        }
        else if(buttonType == 'Next') {
			cmp.set("v.pageNumber",cmp.get("v.pageNumber")+1);
        }
        else if(buttonType == 'Last') {
			cmp.set("v.pageNumber",cmp.get("v.lastPageNumber"));
        }
        console.log('page number: '+cmp.get("v.pageNumber"));
	}
})