On June 6, 1944, the U.S. landed a total 6 divisions at and behind Omaha and Utah beaches.
To defend Normandy, the Wehrmacht had 44 full strength divisions.
Needless to say, the Americans went on the attack against not only the Germans entrenched in the Atlantic Wall (Hitler's vaunted and over-hyped defensive positions that had been recently strengthed by Rommel himself), but we went on the attack also against the Wehrmacht divisions in the rear.
The outcome of the superior American forces is a historical fact, even though they were outnumbered on that day.
And it's an easy thing to teach to your children. The date, 6/6/44 matches the disposition of American versus German forces in Normandy.