Week 3 of 5

Compare plans fairly: phones, pay later and costs over time

Session 1 · SOLVE: Organise Information

Phone plan face-off

10 minHook: a $20 plan that renews every 28 days, and a $22 plan that renews every month. Which costs more in a year? Predict first.
20 minOrganise three or four real plans in a table: upfront cost, cost per period, periods per year (52 weeks ÷ 4 = 13 renewals for a 28-day plan), and yearly total.
15 minAdd the handset: buy outright, or pay monthly over 24 months? Find the total over two years for each option.
5 minRank the plans for three different users: light, medium and heavy data users.

Session 2 · SOLVE: Link Ideas

10 minWrite each plan as a rule: total cost = cost per month × months + upfront cost.
20 minGraph the plans over 24 months on one set of axes (paper or Desmos). Where do the lines cross, and what does that point mean?
15 minBuy now, pay later: $240 split into four fortnightly payments of $60. What if one payment is missed and a late fee is added? Work out the extra cost as a percentage.
5 minWrite a one-sentence rule of thumb for comparing any plan.

Getting started

Use a table with the same headings for every plan so they are easy to compare.

Stretch

Solve the crossover point with algebra: when does 25m + 300 equal 40m + 60?

Checkpoint

A fair yearly (or two-year) comparison of at least three options, with a graph and a clear recommendation for one user.

Activities for this week

Phone plan face-off: Which phone plan is really cheapest over a year, and for whom?
The real cost of 'pay later': What does buy now, pay later cost when things go right, and when they don't?

Useful this week