Equation 1 · Part 7 · The Longest Childhood: Life-History Theory and the Grandmother Bet
fraction
fraction
What this part means
Divide the expression above the line by the one below it.
Its job in the formula
The expression above the fraction bar is divided by the complete expression below it. The denominator must not be zero.
Full expression→fraction→Article meaning
The passage around this formula
Put the three numbers next to each other and the puzzle sharpens rather than resolving. A species that weans early is, on the usual mammalian logic, moving resources toward producing more offspring faster. A species that delays first reproduction by five years relative to a close comparator is, on the same logic, moving resources the other way, into growth and skill before any output. A species in which a large share of the reproductively spent population survives for decades afterward is carrying dependents — grown or not — who cannot be explained by ordinary offspring investment, because offspring investment stops paying by the time the investor can no longer reproduce. The three facts do…
Learn the underlying idea
A fraction a/b means a divided by b. The top number is the numerator; the bottom number is the denominator, and it cannot be zero.
Open the illustrated fractions: division written vertically guide →
Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.