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When adding and subtracting using negative numbers, we think "make more" when we see the addition (+) sign and "make less" when we see the subtraction (-) sign.
5 + -6 =
5 [make more] [negative] by 6 =
If we make a number more negative, we are going to move left on a numberline. We start on 5 and move 6 places to the left. The answer will be -1.
-2 - 7 =
-2 [make less] [positive] by 7
If we make a number less positive, we are going to move left on a numberline. We start on -2 and move 7 places to the left. The answer will be -9.
Another way to think about this is that the negatives are the "rebels" who make us go the other way along the numberline.
For more practice questions, visit www.mathsbot.com/starter , select 'negative numbers'.
Please note that multiplying and dividing is not necessary for Year Six, but if you would like to try, we remember that multiplying or dividing the same will make a positive number and multiplying and dividing by different will make a negative number:
positive x positive = positive 5 x 4 = 20
positive x negative = negative 5 x -4 = -20
negative x positive = negative -5 x 4 = -20
negative x negative = positive -5 x -4 = 20
1km = 1,000m (kilo means 1,000)
1m = 100cm = 1,000mm (cent means 100) (mille means 1,000)
1l = 100cl = 1,000ml (cent means 100) (mille means 1,000)
1 hour = 60 minutes
1 minute = 60 seconds
Whatever we do to one side, we have to do to the other:
What have we done to 1km to get to 1,000m? (multiplied by 1,000 -- moved three places to the left) so we will do the same to work out 8km.
Approximate Metric and Imperial Equivalents
8 kilometres (km) = 5 miles
1 metre (m) = 3 feet
1 kilogram (kg) = 2.2 pounds
1 litre (l) = 1.7 pints
2.5 centimetres (cm) = 1 inch
100 grams (g) = 3.5 ounces
I = 1
V = 5
X = 10
L = 50
C = 100 (think: cent)
D = 500
M = 1,000 (think: mille)
On the left we take away, on the right we add:
5+2 = 7
10 - 1 = 9
Area and Perimeter
Our key points to remember:
Area of a triangle: (base x height) ÷ 2
Area of a parallelogram: base x height
Area of a rectangle or square: 'Areaaah is length x width'
Perimeter means length
Thursday 1st December 2016: Problem-Solving
Today we solved a tricky puzzle in which we had to find out which scripts matched each number. There was some great discussion to be had.
There are six numbers written in five scripts.
Can you match up the correct number with each script?