Chapter 02 · The mechanics
How the family bank works.
Exact math underneath and three jars on top. Saving grows every day. This page walks through each part.
01
The jars
Three jars, fixed.
Spending, Giving, and Saving. Every kid has the same three jars, and every payday lands across them. The share each jar gets is yours to set, per kid.
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 gifts and causes. Giving is one-way: once money lands there, the only way out is a gift or donation an Adult records.
The jar that grows.
Grows a little every day. Moving money back to Spending asks the kid to confirm first.
02
The record
Each payday is recorded once.
Under each jar balance is a record of every move, exact to the cent. Money moves from one place to another, and both sides of each move agree. It is the rigor a bank uses, scaled 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 grows, daily.
At the family's local midnight, each kid's Saving jar grows by one day's share of the rate an Adult set. Each day's growth is posted to the jar, so the kid can watch the balance build.
| 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.
A few moves happen on their own. The rest ask the kid to confirm, or wait for an Adult. The table lists every case.
| The move | What happens |
|---|---|
| Spending → Saving (kid) | Auto |
| Saving → Spending (kid) | Kid confirms |
| Giving it away | Adult confirms |
| Any spend request (kid) | Adult confirms |
| Any move (Adult) | |
| Undoing anything |
05
History
Corrections stay in view.
Once money moves, the record of it stays. If something is wrong, an Adult undoes it, and the undo becomes part of the story: the original is struck through and stays visible beside the fix, with the reason the Adult gave.
| 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 · Grandma | $10.00 |
06
Practice money
Every balance is practice money.
Twiggybank keeps balances in whole cents of the currency your family picks, and no cash moves anywhere. It holds no funds and is not a money transmitter, and no balance in it is insured. It is an educational money tracker.