diff --git a/src/api-l.js b/src/api-l.js
index 7f44d4f..4a6f2ab 100644
--- a/src/api-l.js
+++ b/src/api-l.js
@@ -43,12 +43,12 @@ exportSymbolL('WebGLEarth.prototype.setView', function(center, opt_zoom) {
 
 
 exportSymbolL('WebGLEarth.prototype.zoomIn', function(opt_delta) {
-  this.setZoom(this.getZoom + (goog.isNumber(opt_delta) ? opt_delta : 1));
+  this.setZoom(this.getZoom() + (goog.isNumber(opt_delta) ? opt_delta : 1));
 });
 
 
 exportSymbolL('WebGLEarth.prototype.zoomOut', function(opt_delta) {
-  this.setZoom(this.getZoom + (goog.isNumber(opt_delta) ? opt_delta : 1));
+  this.setZoom(this.getZoom() - (goog.isNumber(opt_delta) ? opt_delta : 1));
 });