וַתְּהִי עוֹד מִלְחָמָה בְּגַת וַיְהִי אִישׁ מָדוֹן וְאֶצְבְּעֹת יָדָיו וְאֶצְבְּעֹת רַגְלָיו שֵׁשׁ וָשֵׁשׁ עֶשְׂרִים וְאַרְבַּע מִסְפָּר וְגַם-הוּא יֻלַּד לְהָרָפָה
There was war in Gath again, where there was a champion who had six fingers and six toes each, for a total of twenty-four. He was also born to the giant.
Rashi quotes the Talmud in Bechoros: Why tell us that he had a total of 24, which we could easily calculate? Because people might err and think that the warrior had a total of six fingers and six toes, not six digits on each hand or foot. So then why not just tell us 24 and leave out the part about six each? Because then people might mistakenly think that he had one normal hand and foot of five digits each and one mutated hand and foot of seven.