Did you know that Calvin wrote a catechism? He wrote it as a dialogue between a Minister of the Gospel and a child. You can find it here. The following is a sample. (Do you think your child could provide these answers? How about you?)

34. What, next, is meant by the name of Christ?
By this title His office is still better expressed—for it signifies that He was appointed by the Father to be ordained King, Priest, and Prophet.
35. How do you know that?
Because according to the Scripture, anointing is used for these three things. Also, because they are attributed to Him many times.
36. But with what kind of oil was He anointed?
Not with visible oil as was used for ancient kings, priests, and prophets, but this anointing was by the grace of the Holy Spirit, who is the reality signified by that outward anointing made in time past (Isa. 61:1, Ps. 45:7).
37. But what is this Kingdom of which you speak?
It is spiritual, and consists in the Word and Spirit of God, and includes righteousness and life.
38. What of the priesthood?
It is the office and prerogative of presenting Himself before God to obtain grace and favour, and appease His wrath in offering a sacrifice which is acceptable to Him.
39. In what sense do you call Christ a Prophet?
Because on coming down into the world (Isa. 7:14) He was the sovereign messenger and ambassador of God His Father, to give full exposition of God’s will toward the world and so put an end to all prophecies and revelations (Heb. 1:2).
40. But do you derive any benefit from this?
All this is for our good. For Jesus Christ has received all these gifts in order that He may communicate them to us, and that all of us may receive out of His fullness.
41. Expound this to me more fully.
He received the Holy Spirit in full perfection with all His graces, that He may lavish them upon us and distribute them, each according to the measure and portion which the Father knows to be expedient (Eph. 4:7). Thus we may draw from Him as from a fountain all the spiritual blessings we possess.
42. What does His Kingdom minister to us?
By it, we are set at liberty in our conscience and are filled with His spiritual riches in order to live in righteousness and holiness, and we are also armed with power to overcome the devil, the flesh, and the world—the enemies of our souls.
43. What about His priesthood?
First, by means of it He is the Mediator who reconciles us to God His Father; and secondly, through Him we have access to present ourselves to God, and offer Him ourselves in sacrifice with all that belongs to us. And in this way we are companions of His priesthood.
44. There remains His Prophetic Office.
Since this office was given to the Lord Jesus to be the Master and Teacher of His own, its end is to bring us the true knowledge of the Father and of His Truth, so that we may be scholars in the household of God.
45. You would conclude, then, that the title of Christ includes three offices which God has given His Son, in order to communicate virtue and fruit to His faithful people?
That is so.