Tables: where did this month’s money go?

Let AI group the numbers, then check a few important totals yourself.

What you will make

Get monthly totals, category differences, and a readable spending summary.

Example result

September 2100 → October 2350 TWD.
Up 250, about 11.9%; meals increased by 150.

This is a prepared example. Your AI may use different wording.

Follow along

Work in your own AI tool

Practice material

Fictional spending; purchase-month basis; all TWD. Positive values are spending; negatives are refunds.
ID,Month,Category,Amount
S01,2026-09,Meals,1200
S02,2026-09,Transport,400
S03,2026-09,Services,500
O01,2026-10,Meals,1350
O02,2026-10,Transport,450
O03,2026-10,Services,550

Request for AI

Using these six rows, calculate September and October totals, the increase, and percentage increase to 1 decimal. Show the change in each category. First find categories with an increase greater than 50.

1. Paste the six rows and request into AI to get a spending summary.
2. Use a calculator to check September 2100, October 2350, and an increase of 250.
3. Then send: “Change greater than 50 to at least 50. Which categories appear?” Watch the result change from 1 category to 3.
4. Try: “Add an October meals refund of -100 and recalculate.” October should become 2250. Save the explanation you find clearest.

After trying: compare a possible result

Original six rows: September 2100; October 2350; increase 250; 250÷2100×100≈11.9%. Categories: meals +150, transport +50, services +50. >50 selects meals only, 1 category; >=50 selects 3. Monthly totals do not change. After an October meals refund of -100: October 2250, increase 150, 150÷2100×100≈7.1%; net meals 1250, with all three categories +50.

Check these parts of your result

The original totals are 2100 and 2350: an increase of 250, about 11.9%.
Greater than 50 selects meals; at least 50 selects all three categories.
After the -100 refund, October is 2250: up 150, about 7.1%.

Try a different situation yourself

New fictional TWD data: September books 300, transport 200; October books 360, transport 240. Calculate monthly totals and percentage change, then compare category increases >40 and >=40.

September 500; October 600; increase 100, 20.0%. Books +60, transport +40. >40 selects 1 category; >=40 selects 2. Thresholds do not change totals.

Try a more involved task

Handle missing amounts, a zero baseline, and different currencies together.

Fictional category data: September courses 0 TWD, meals 100 TWD; October courses 200 TWD, meals amount missing, books 10 USD. No exchange rate; do not guess amounts.

List known subtotals by currency, unknowns, and valid differences. Can the courses percentage be calculated? Can a complete October total or overall percentage change be claimed?

September known TWD total is 100. October known TWD subtotal is 200 with meals unknown; the separate 10 USD cannot be added directly. Courses increase by 200, but percentage change is undefined with a zero baseline. The complete October total and overall percentage change are unconfirmed; a known subtotal is not a complete total.

Save your work and continue later

Save the AI response in your own notes and add one sentence about what you changed. You can also use the optional record below.