Why do some of the gospel accounts of the resurrection say three women went to the tomb and others say only one? There also seem to be other differences. If these contradictions are real, how can I deal with them?
The resurrection accounts in the gospels do have some differences in detail. How many women went out to the tomb that morning, one (Jn 20:21), two (Matt 28:1), or three (Mk 16:1)? How many angels did they see that morning, one (Matt 28:2; Mk 16:5) or two (Lk 24:4; Jn 20:12)? Did the women run to the disciples and tell what they had seen (Mt 28:8; Lk 24:9) or did they say nothing out of fear (Mk 16:8)? Did Jesus see them first in Galilee (Mk 16:7; Mt 28:9) or in Jerusalem (Lk 24:36)? Among the Apostles, did he appear to Peter first (Lk 24:34), all eleven at once (Mt. 28:16), or the eleven minus Thomas (Jn 20:24)? Did Jesus appear to them in a room (Jn 20:19) or a mountaintop (Mt 28:16)? Lastly, did Jesus ascend on Easter Sunday (Lk 24:50-53; Mk 16:19) or forty days later (Acts 1:3-9)?
Most of these apparent discrepancies are not actual conflicts upon closer examination and are easily explained. We cannot look at them all in a short column. But as to your specific question, it would seem most likely that several women went out that morning. That John only focuses on Magdalene is not a denial that others were there. Matthew and Mark, in saying two or three may not be engaging in a headcount per se, but engaging in generalization, such as when we say words like, couple or several.
We should not be surprised that there are some differences in the accounts. Even today, eyewitnesses of an event often emphasize certain details and have different recollections as to the particulars. People often summarize longer stories as well and speak only of essentials. This does not mean that the event did not happen or that unmentioned details by one person is in conflict with details mentioned by another. Given the numerous times Jesus appeared and the many people who saw him, we should not be surprised to find certain differences in the accounts. In this light the differences actually lend credibility to the gospel accounts, which do not try to paper over them, but realistically report them. (See Catechism #s 642-643)
"Building our Catholic faith one question at a time."