The story in three lines. Two crews each built "half" of a footbridge across a river twelve planks wide, but one built eight and one built six, so the ends overlap. Inkling wants to saw a plank off each end, until Bundle asks what the whole is. The children measure the whole, see the difference, fold the rope into two equal halves, and the east crew lifts two pegged planks out to make a railing.

One question to ask. "Seven and five would have fitted. Why weren't they halves?" Halves are two equal parts. If your child says "because seven is bigger", ask how they could check without counting.

One thing to do at the table. You need a piece of string, a pair of scissors, and something to share (a strip of paper, a slice of toast). Fold the string end to end so the ends meet: the fold is the middle. Cut the strip of paper "in half" by eye, then lay the pieces side by side. Is one longer? By how much? Fold and cut again.

The grown-up layer. Children often call any two pieces "halves", and "the bigger half" is a common phrase. This book separates the whole (twelve), the parts (six and six) and the difference (two). That is the start of the bar model taught in Singapore-style maths, where a story problem is drawn as bars before it is solved. Folding to find a half works because folding matches every part of one side with the other.

Let your child tell the story back in their own words first. Telling it back is how the even-rule goes on the belt.