Augustine of Hippo — as excerpted in the Catena Aurea on Mark 6:35-44

“(Con. Evan. 2. 46) This in the Gospel of John is the answer of Philip, but Mark gives it as the answer of the disciples, wishing it to be understood that Philip made this answer as a mouthpiece of the others; although he might put the plural number for the singular, as is usual. It goes on, And he saith unto them, How many loaves hare ye? go and see. The other Evangelists pass over this being done by the Lord. It goes on, And when they knew, they say, Five, and two fishes. This, which was suggested by Andrew, as we learn from John, the other Evangelists, using the plural for the singular, have put into the mouth of the disciples. It goes on, And he commanded them to wake all sit down by companies upon the green grass, and they sat down in ranks by hundreds and by fifties. But we need not be perplexed, though Luke says that they were ordered to sit down by fifties, and Mark by hundreds and fifties, for one has mentioned a part, the other the whole. Mark, who mentions the hundreds, fills up what the other has left out.”