Session 1 · SOLVE: Link Ideas
Aotearoa on a number line
- 10 minHook: Ranfurly −25.6°C, Scott Base in winter, a summer day in Alexandra, a diver at the Poor Knights, Aoraki/Mt Cook at 3,724 m. Which numbers are below zero?
- 20 minBuild two vertical number lines in the corridor: temperature (−30°C to 40°C) and height (sea level at 0). Place real NZ cards on them.
- 15 minWork out gaps: from −25.6°C to 20°C; from a diver at −18 m to a lookout at 45 m. Use the number line to show adding and subtracting across zero.
- 5 minLink: why is 'going up' from −5 to −2 a rise of 3 and not 7?
Session 2 · SOLVE: Link Ideas
Order matters, and the first code
- 10 minCalculator battle: type 3 + 4 × 2 into different calculators and phones. Why do some give 11 and some 14?
- 15 minLearn GEMA (grouped, exponents, multiply and divide, add and subtract). Four 4s challenge: make every number from 0 to 10 using exactly four 4s and any operations.
- 20 minCaesar wheel: make a split-pin cipher wheel. Encode a short message with a shift of 3, swap with another pair and decode theirs.
- 5 minLink: where could a Caesar shift, an integer or a GEMA calculation become a lock in our escape room?
Getting started
Start with whole-degree temperatures and a number line from −10 to 10 before using the full NZ range.
Stretch
Encode a message with a shift of −5 (backwards). Then find a single shift that undoes a shift of 7 followed by a shift of 11.
Checkpoint
Students can place, order and find the difference between positive and negative numbers and evaluate a three-operation expression in the right order.
Activities for this week
- Aotearoa number line: How do negative numbers help us describe Aotearoa's hottest, coldest, highest and deepest places?
- Four 4s and the calculator battle: Why do mathematicians agree on an order of operations?
- Caesar wheel and frequency detective: How can a code be broken without the key?
Useful this week
- Positive and negative numbers ↗ Adding and subtracting across zero, shown on a number line.
- Otago region: climate, plants and animals ↗ Where New Zealand's record low temperature of −25.6°C was measured.
- CS Unplugged topics ↗ New Zealand-made activities on binary, codes and error detection without computers.