Saving up
For the grown-up beside a child who loves saving up.
The child's own door is Saving up on Spark & Anvil.
Three numbers to notice
- A price, and how much is already saved toward it. The gap is a subtraction anyone can do.
- How many weeks of saving the gap would take: the gap divided by the weekly amount, rounded up.
- A rate on a sign or a statement. At 6% a year, money takes about 72 ÷ 6 = 12 years to double.
On the way home, ask: “What would you save up for, and how many weeks do you think it would take?”
Ask because you are curious, and let any answer stand. Print this page for a half-page card.
A short course for you
- Money, Drawn4 lessons. Four everyday money ideas, each drawn as a strip of paper: a paycheck's parts, a tax bracket as a cut bar, interest as last year's bar plus a slice, and a loan's shrinking interest.
- Money Decisions, Out Loud3 lessons. Three short lessons for the parent of a teenager: think a real money decision out loud, show why the maths matters to their own life, and let them make the next call.
- The Price of Waiting3 lessons. Three short lessons for the parent of a teenager with a first account: why growth over time is bigger than it looks, the rule of 72, and what a small yearly fee costs over thirty years. Every rate here is an assumption, not a promise.
A little history, and what nobody knows
The rule of 72
The earliest known mention of the rule of 72 is in Luca Pacioli’s Summa de arithmetica of 1494, which states the rule without showing where it comes from.
Because Pacioli gives no derivation, how the rule was first found is not known.
Source: Rule of 72 (Wikipedia)
The same idea at every age
- Ages 3–5Save Up for It
- Ages 6–8Weeks to the Goal
- Ages 9–14Compound Growth and 1 more
- Ages 15–18Time Multiplies and 3 more
Your child will meet this idea again at every age. The tools and courses here are the part for you.