The multiplication rule
Types of exercises: the multiplication rule, arranging in order, codes and sequences of outcomes, numbers whose digits meet conditions, filling places in order, counting numbers built from given digits, neighbouring parts in different colours.
Exercises are drawn at random from a large bank - every click gives a different set.
Solved: 0 of 10
Problem
How many 2-digit numbers have only even digits?
Problem
A 4-sided die is thrown 2 times. How many different sequences of results are there?
Problem
A shelf holds 12 different books. In how many ways can 2 of them be put in a row, if the order matters?
Problem
How many 4-digit numbers can be built from the digits 2, 3, 6, 7, 8, if the digits may repeat?
Problem
There are 3 ice cream flavours, 2 sauces and 8 toppings to choose from. We choose one item from each group. In how many ways can this be done?
Problem
A queue will be formed by 8 people, Anna among them. In how many ways can they line up if Anna is to stand second in the queue?
Problem
A flag has 5 vertical stripes. Each stripe is painted in one of 6 colours, and neighbouring stripes must have different colours. The stripe next to the flagpole must be white - white is one of these colours. How many such flags are there?
Problem
How many 5-digit numbers have only odd digits?
Problem
A code consists of 3 digits. How many different codes are there?
Problem
There are 21 runners in a race. In how many ways can the first 3 places be taken?
This address is one particular set - everyone who opens it gets exactly the same exercises. Copy the link from the address bar and send it to the class. You can generate a new set at the top of the page.
PhiBoard is a free online whiteboard for maths
These exercises are part of it. On the board itself you can plot a function, write a formula in LaTeX, or solve a problem together with a teacher or a friend - live, in the browser. Our app is completely free.