# P6 Numeracy 11th March

Solve a Maths Codeword and then find the missing angles with each parallelogram.

Warm-up activity

Today's warm-up features a Maths Codeword.  A codeword is set out like a crossword but, when you look closely, you will see that there is a number at the top of each square.  These numbers range from 1 to 26 and each number represents one letter of the alphabet.

To complete the codeword, we need to solve the clues at the bottom of the page.  Watch today's video where Mrs Bell demonstrates how to do this.  For the higher level task, the first clue says

7 X 5 = 35    35 - 14 = 21   This means that, wherever I see 21 in the codeword, I should write the letter P in the same box.

As you solve the clues and write the matching letters into the squares, you will begin to create different words in your codeword.  Once you have written a letter in every square, look carefully at each word.  One of the words will be a Maths word - can you find it?  Write this Maths word at the bottom of your page.

Main activity

Today we are going to revisit quadrilaterals (shapes with four straight sides) and revise our work on parallelograms and their angles.  We learned back in term one that the angles inside all quadrilaterals  (the internal angles) must add up to 360o.

For example, a rectangle has four right angles.  Each right angle measures 90o so 90o X 4 = 360o

Before you begin, it would be a good idea to rewatch this Maths Mansion episode which is all about squares, rhombuses, rectangles and parallelograms.

## 34 Better Get Back into Shape and Be a Square

Naming and classifying quadrilaterals using criteria such as parallel sides, equal angles and equal sides

For today's lesson, we are going to concentrate on parallelograms.  We learned in term one that, in a parallelogram, opposite angles are equal.

Look closely at this parallelogram.

We can see that angle A = 40o.  Which angle is opposite angle A?  To find out, draw an imaginary diagonal line from angle A and you will arrive at angle C.  If opposite angles are equal, we now know that angle C = 40o too.

If angles A and C are both 40o, then we have already used up 80o

To work out the size of angles B and D, we need to subtract this 80o from 360o to see how many degrees are left

I now have 280o which must be shared equally between angles B and D so I need to divide it in two

280o ÷ 2 = 140o so angles B and D are each 140o.

Watch today's video where Mrs Bell looks at more examples and then have a go at today's written activity.  Don't forget to do your working-out please and do remember to include the degrees symbol (o) in your answers!

Reasoning activity