The four operations
Types of exercises: mental addition and subtraction, mental multiplication and division, calculating cleverly, comparing by difference and by ratio - mentally, comparing in a word problem - mental calculation.
Exercises are drawn at random from a large bank - every click gives a different set.
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Solved: 0 of 10
Problem
A bike costs 720 zloty and a scooter costs 4 times less. How much cheaper is the scooter than the bike?
Problem
Which number is 85 less than 566?
Work it out in your head
950 999 + 5
Work out
30 · 600
Calculate cleverly
26 + 46 + 74
Problem
A backpack costs 210 zloty and a pencil case costs 7 times less. How much cheaper is the pencil case than the backpack?
Problem
How many times greater is 84 than 12?
Work it out in your head
65 − 37
Work out
200 : 50
Calculate cleverly
15 · 101
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.