The Torah sets forth that if someone makes an oath to give the value of a specific person to the Beis HaMikdash, the amount due depends on that person’s age and gender. For a male from age one month until five years, the amount due is five Biblical shekalim; from the age of five until twenty, twenty shekalim; from twenty until sixty, fifty shekalim; from sixty onward, fifteen shekalim. For a female, from age one month until five years, three shekalim; from five until twenty, ten shekalim; from twenty until sixty, thirty shekalim; from sixty onward, ten shekalim.

It is common for someone going through a time of danger or distress to make this type of oath (Abarbanel). A Jew blames his troubles on his own shortcomings because “there is no suffering without iniquity and there is no death without sin” (Shabbos 55a), and he seeks to atone for himself by donating his value to the Beis HaMikdash. If it is someone else who is in danger or distress, one might choose to donate that person’s value as a merit for salvation. In His mercy, Hashem is willing to accept a meaningful monetary donation of this type as a redemption. He proclaimed: “If you donate to Me your monetary value, I will consider it as if you offered your souls before Me and I will spare you from Gehinom" (Midrash Tanchuma §6). We lost this avenue of redemption with the destruction of the Beis HaMikdash, but acts of charity can accomplish a comparable effect.

For each stage of life, the Torah indicates the value that Hashem is willing to accept as a symbolic representation of the person, even though that person might actually be worth a lot more. To illustrate this point, Moshe himself was over sixty at the time when he spoke this mitzvah,and the amount of his actual worth is too large to type on a calculator. Yet, the Torah accords him a value of only fifteen shekalim, for that is the standardized amount for his age group.

Hashem did not require an actual evaluation of the person’s worth in the manner one might evaluate slaves because many would find this degrading, especially when two people are evaluated and one is accorded a higher value. Moreover, a person would be willing to all of his money and more for his life! Hashem therefore chose to evaluate people in a general and impersonal manner, based on categories that are divided by age and gender (Abarbanel).

A verse in Tehillim (90:10) states that a person generally lives between seventy and eighty years, and it follows that the center and prime of a person’s life is approximately between 20 and 60. We therefore find that whenever the Torah counts the Jewish people, it focuses on this age group. Within this age group, a person’s physical strength peaks at thirty and begins to wane at fifty, and we thus find that the Leviim served in the Mishkan only when they were between these ages (Bamidbar 4:3). Since a person’s intellectual faculties increase with age, it appears that fifty is the combined physical and intellectual peak. Sixty is the beginning of the final quarter, and it is then that old age begins to set in (Avos 5:21). The above will help us understand the Torah’s four age groups and their redemption values.

A newborn does not have a set value until the age of a month because until then his viability is considered uncertain (see Shabbos 135b). From one month until age five, his value is five shekalim, and then it increases to twenty until age twenty.The division of age groups at five years is in line with the Gemara’s caution against intense Torah studies until that age, for health reasons (Emek Davar). Regarding the age groups one month until five years and five years and until twenty years, we may suggest that the Torah accorded a value corresponding to the maximum age of the category, five shekalim and twenty shekalim respectively. Between ages twenty and sixty though, a male’s value is fifty shekalim and not sixty, because the body deteriorates between fifty and sixty. For the category that extends from sixty until very old age, the Torah deducts a majority of a person's value, decreasing from fifty to fifteen. Alshich explains this to be a decrease of two-thirds, rounded down to the nearest unit of five.

In general, the Torah accords a female a redemption value that is a bit more than half of that which it accords a male of the same age group (see Chizkuni). The approximately doubled amount reflects the male’s additional strength (Abarbanel), Torah and mitzvos (Alshich), and influence on society (Rav Hirsch). We may add that since a male has more mitzvah obligations, in the event that he fails to meet those greater obligations, he requires a greater amount for redemption. Accordingly, until age five, a female’s redemption value is three shekalim instead of five, and between twenty and sixty, her redemption value is thirty instead of fifty, which is sixty percent. It emerges that both males and females are valued as children until age five at a tenth of their value as fully-grown adults between ages twenty and sixty (Abarbanel), for the number ten symbolizes completion (Maharal, Bava Metzia 84a).

Beyond sixty, we encounter an apparent discrepancy in the proportion of decrease in redemption value: a man’s value decreases from fifty to fifteen, which is a seventy percent decrease, and a woman’s value decreases from thirty to ten, which is only a sixty-six percent decrease. Rashi explains that an old woman’s redemption value is close to that of an old man because as the saying goes, “An old man at home is a burden; an old lady at home is a treasure.” Meaning, when a man becomes old and loses much of his physical strength, his ability to work and contribute to the household diminishes in parallel, and he is not accustomed to applying himself to housework that is still within his capacity. An old woman, on the other hand, will largely continue performing her household chores despite her lessening of vigor. In addition, Alshich observes that old age seems to take a greater toll on men than it does on women.

That which the Torah accords a female most of the redemption value it accords a male appears to suggest an element of equality, in accordance with the Talmudic rule, “the majority is like the whole” (Nazir 42a). In other words, although a man has more strength, Torah and mitzvos, and social influence, a woman’s value is comparable even in those respects. However, between the ages of five and twenty, the redemption value of a female is ten shekalim while a male’s is twenty shekalim, which is fully double. Hashem seems to be indicating that in this particular age group, the redemption value of males is on an entirely different level. How can we understand this?

The Mishnah in Avos (5:21) sets forth that a Jewish boy begins his Torah studies at age five, and it designates eighteen as the age for marriage and twenty as the age when the responsibility for his growing family generally compels him to pursue a livelihood. It emerges that between five and twenty, a Jewish male should be entirely and purely dedicated to attaining knowledge of Hashem by acquiring the wisdom of His Torah. Girls do not carry this great responsibility. We may therefore suggest that on account of the supreme importance of the Torah studied by males during their formative years between five to twenty, the Torah doubles their redemption value.