How to count in 50s
Counting in 50s is very similar to your 5 times table.
Let's count in 5s:
5, 10, 15, 20, 25, 30 鈥
Now let's count in 50s:
50, 100, 150, 200, 250, 300 鈥
What do you notice?
Counting in 50s is just like counting in 5s but with an extra zero. This is because the numbers are ten times bigger.
Example 1
What numbers are missing from this sequence?
300, 鈥 , 400, 450, 鈥
Use your knowledge of the 5 times table and reduce the size of each number by dividing by 10.
That sequence would go:
30, 35, 40, 45, 50
Now multiply the numbers by 10 again to find the answer.
300, 350, 400, 450, 500
The missing numbers are 350 and 500.
Example 2
There are 50 chocolates in each box. Maja ordered 7 boxes.
How many chocolates are there in total?
Use a number line to find 7 lots of 50:
There are 350 chocolates in 7 boxes.
Another way you could have worked this out is by using your 5 times table knowledge.
If 5 x 7 = 35, then 50 x 7 = 350, because when you count in multiples of 50, it is 10 times greater than counting in multiples of 5.
Example 3
Which number in this sequence is the odd one out?
700, 650, 600, 555, 500, 450
What do you know about multiples of 50?
They鈥檙e very similar to the 5 times table, but 10 times greater.
They end in a zero.
Which of these numbers don鈥檛 follow those rules?
555 looks very similar to 55 which is a multiple of 5, but it doesn鈥檛 end in a zero.
So 555 is the odd one out.
Activity
Quiz
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