Chapter 02 · The mechanics
How the family bank works.
Penny-accurate math underneath, three jars on top, and a daily growth tick that turns the Saving jar into a teacher. Here’s the whole machine, opened on the workbench.
01
The buckets
Three envelopes, fixed.
Spending, giving, saving. Same three for every kid, every family, every payday. The mix is yours to set; the labels are yours to translate (some families call them now, share, later); the model underneath does not change. Consistency is the teaching tool.
Day-to-day money.
Pocket cash. The kid decides what happens to it — within the limits the family sets. Defaults to half the payday.
For someone else.
A small slice for charity, gifts, or community. Giving is one-way: once allocated, the only exit is a real donation the parent confirms.
The jar that grows.
Grows a little every day, compounding. Moving money out of saving requires asking — the equivalent of breaking the piggy bank.
02
The honest record
Every payday is one tidy event.
Under each jar balance is a real, penny-accurate record. Money never appears or disappears — it moves from one place to another, and both sides always agree. The same rigor a bank uses, scaled down to a single family.
| Where it goes | Amount |
|---|---|
| Sarah · Spending | $2.50 |
| Sarah · Giving | $1.00 |
| Sarah · Saving | $1.50 |
| $5.00 in, shared three ways — to the penny. | $5.00 |
03
Saving grows
Saving compounds, daily.
At the family's local midnight, each kid's Saving jar grows a little. Daily compounding, fractional-cent remainders carried so nothing drifts. The result: most days the saving line ticks up by a cent or two, and the kid watches it happen.
| May 19 | $120.34 | +$0.03 |
| May 20 | $120.37 | +$0.03 |
| May 21 | $120.40 | +$0.03 |
| May 22 | $120.43 | +$0.03 |
| May 23 | $120.47 | +$0.04 |
04
Asking
What requires permission.
Some moves are automatic. Some require a parent. The list is short and deliberate — the boundary between the two is where most of the conversations happen.
| The move | What happens |
|---|---|
| Spending → Saving (kid) | Auto |
| Saving → Spending (kid) | Asks first |
| Giving it away | Asks first |
| Any spend request (kid) | Asks first |
| Any move (parent) | |
| Undoing anything |
05
Honest history
Money has a memory.
Once money moves, that fact can't be quietly edited. If something is wrong, a parent fixes it — and the fix is itself part of the story, struck through but visible alongside the original. The history is add-only. The lesson is implicit: an honest record doesn't forget.
| May 22 | Allowance · Sarah | $5.00 |
| May 21 | Snack money · Sarah | $3.50 |
| May 21 | Fixes the snack-money mistake | $3.50 |
| May 20 | Birthday gift · Mum | $10.00 |
06
The honest part
It is not a real bank.
No money actually moves. Balances are integer cents of a configurable currency — pretend money, but real math. We hold no funds, we are not FDIC insured, and we are not a money transmitter. We are an educational money tracker. The door is open to real balances later; nothing in the product settles cash today.