The first week back after the holidays, we will be looking at place value. We will be rounding numbers up to 1,000,000 to the nearest 10, 100, 1000, 10000 or 100000.
Giving the complete number for something is sometimes unnecessary. For instance, the attendance at a football match might be 23745. But for most people who want to know the attendance figure, an answer of ‘nearly 24000‘, or ‘roughly 23700‘, is fine.
We can round off large numbers like these to the nearest thousand, nearest hundred, nearest ten, nearest whole number, or any other specified number.
Round 23745 to the nearest thousand.
First, look at the digit in the thousands place. It is 3. This means the number lies between 23000 and 24000. Look at the digit to the right of the 3. It is 7. That means 23745 is closer to 24000 than 23000.
Next week the children will be recognizing and using square numbers and cube numbers, as well as knowing the notation for square 2 and cubed 3.
Squaring a number
32 means ’3 squared’, or 3 x 3.
The small 2 is an index number, or power. It tells us how many times we should multiply 3 by itself.
Similarly 72 means ’7 squared’, or 7 x 7.
And 102 means ’10 squared’, or 10 x 10.
So, 12 = 1 x 1 = 1
22 = 2 x 2 = 4
32 = 3 x 3 = 9
42 = 4 x 4 = 16
52 = 5 x 5 = 25
1, 4, 9, 16, 25… are known as square numbers.
Cubing a number
2 x 2 x 2 means ’2 cubed’, and is written as 23.
13 = 1 x 1 x 1 = 1
23 = 2 x 2 x 2 = 8
33 = 3 x 3 x 3 = 27
43 = 4 x 4 x 4 = 64
53 = 5 x 5 x 5 = 125
1, 8, 27, 64, 125… are known as cube numbers.
Next week, we will be solving addition and subtraction multi-step problems in contexts, deciding which operations and methods to use and why.
The children will be facing problems such as this;
239,990 people travelled by train in July and August.
12,890 more travelled by train in July than in August.
How many in total travelled by train in July and August?
How did you work this out?
From this, the children will break down the steps and figure out what calculation they have to do. In this instance, they will be adding the two sets of numbers to find the total amount of people who travelled on the train. They will have to show their workings out using the correct method.
Next week the children will be looking at decimals. In particular, the children will be rounding decimals with two decimal places to the nearest whole number and to one decimal place. They will also be reading, writing, ordering and comparing numbers with up to three decimal places.
Decimal places are counted from the decimal point:
So, the number has four decimal places, while has two decimal places.
Round to decimal places
This means we need digits after the decimal point.
Because the next digit , is more than , we round the up.
( decimal places)