Standard Index Form Matching

Why do this problem?

This problem offers an excellent opportunity for students to practise working with numbers and calculations expressed in standard index form.

Possible approach

The game can be played online using the interactive version. Alternatively, print off enough copies of the cards (Set A and Set B) so that students can work in pairs. The top 12 cards and the bottom 12 cards on each sheet form a set of six pairs. The cards becomes progressively more difficult. This means that students can work with a set of 6, 12, 18 or 24 pairs.

Here are some suggestions for games and activities that they could do:

• Shuffle the cards and deal them out face up. Take it in turns to find a matching pair. If your partner chooses two cards and you don't think they form a matching pair, challenge them to explain their reasoning.
• Shuffle the cards and deal them out face up. Time how long it takes your partner to find all the matching pairs. If they match any incorrectly, add a twenty second time penalty. Then swap over. Who can get the fastest time?
• Shuffle the cards and deal them out face down. Turn two cards over at a time. If they match, keep them. If they don't, put them back. Take it in turns until all the cards have been chosen. Who can collect the most pairs?

Whether students have played online or with the cards, set aside some time at the end of the lesson to discuss the strategies they used to work out the calculations, and which pairs they found easiest/most difficult to match.

Key questions

How do you know that two cards match?
Are some pairs easier to match than others?

Possible support

Students could start by just matching the cards in the top half of Set A.

Possible extension

Invite students to create their own sets of cards with tricky examples, which they can then swap with another pair of students.