Biscuit Decorations

Andrew decorated 20 biscuits to take to a party. He lined them up and put icing on every second biscuit and different decorations on other biscuits. How many biscuits weren't decorated?

Number Detective

Follow the clues to find the mystery number.

Skip Counting

Find the squares that Froggie skips onto to get to the pumpkin patch. She starts on 3 and finishes on 30, but she lands only on a square that has a number 3 more than the square she skips from.

Constant Counting

Constant Counting

You can make a calculator count for you by pressing the keys

$1 + = =$

$1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12$

To make it count by twos, press $2 + = =$

$2, 4, 6, 8, 10, 12$

You can make it count by any number you choose.

Now the question:

You can count by ones to reach $24$.
You can count by twos to reach $24$.
What else can you count by to reach $24$?

Why do this problem?

This activity is good for helping pupils learn about factors and multiples while becoming more familiar with a calculator.

Possible approach

Handing out calculators one between two pupils will encourage them to communicate while exploring.

When you bring the children together at the end of the lesson, you may want to emphasise some appropriate vocabulary, depending on their age and experience.

(There is some variation in the constant function in different calculators so you may need to experiment a little to find out how to work it. For example, with some older calculators the key sequence is $1 + + = =$.)

Key questions

How many $2$s did you use?