Calculator Activity - 2

This is a follow-up to our popular Calculator Activity-1.

While that original resource focused exclusively on Addition, this one helps children develop their understanding (and accuracy) when reading written numbers and calculating with both addition and subtraction.

Here is the activity:

The pdf file consists of 3 pages of 8 cards, print out the whole thing and then cut the pages into separate 'cards'.

The children work in pairs; each pair has a number of cards, and a calculator between them. The mix the card face-down between them, and then choose to be either the 'reader' or the 'calculator'.

The 'reader' chooses a card and reads out the numbers and the functions one line at a time (keeping the 'Check' value hidden). Their partner listens carefully and enters the numbers and the functions into the calculator. Once complete, he reveals the final answer, if it matches the 'Check' value on the card they know that both the reader and the calculator user were accurate, as a result they can keep the card!

If the final answer and the 'Check' number do not match they should place the card on the bottom of the pile in order to re-use it later.

The children swap roles and continue until all of their cards have been used.

Notes

• The mixed vocabulary on the cards consists of: Subtract, Take-away, Minus; Add, Plus.
• The calculations are designed to be carried out in the order in which they appear on the cards... they do not take account of BODMAS. For older children it may be useful to discuss this with them... what would happen if the calculations were carried out in a different order? In some cases it would not make any difference? Which ones, why? In other cases, changing the order of the calculations will change the final answer.
• As before, the numbers have not been chosen at random. They have been specifically selected to give children practice.
• The 'Check' numbers have also been chosen so that they are easy to identify; they are all primes.

Adaptations

1. The activity can be timed, eg. how many cards can you complete correctly in 10 minutes?
2. As an extension, the 'reader' can be asked to omit one of the numbers from the list, and instead tell their partner the target value (the 'Check' number) to see if they can determine which number was missed out.
3. A child could carry out the activity independently. The 'Check' numbers are low down on the cards so that if the calculator is placed over the lower part of a stack of cards, they can still enter the numbers and 'test' themselves before pulling the card up to see compare their results.

Here's a thumbnail image of the three page download.

As always, let us know how this activity works for you... or if you develop further adaptations.

We have another version of this activity using all four functions, this is available via the mathsticks+ dashboard.