maths-booster-lesson-2-addition-and-subtraction
Year 6 SATs Booster
Maths 2
Addition and Subtraction Part 1
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Year 6 SATs Booster
Maths 2
Addition and Subtraction Part 1
Objectives:
Use known number facts and place value to help with, and speed up, mental addition/subtraction.
Vocabulary:
digit
more than
less than
sum
difference
Addition
How would you add together
24 and 37 in your head?
24 + 37
Here is one way of doing it. You could partition the numbers.
30 + 20 = 50
37 = 30 + 7
Add the tens
Then add the units
Then add the answers together
24 = 20 + 4
7 + 4 = 11
50 + 11 = 61
So 24 + 37 = 61
24 + 37
Here is another way of doing it.
24 + 37
=37 + 24
=37 + 20 + 4
=57 + 4
= 61
Using a number line.
24 + 37
Another way.
37 + 24
= 37 + 4 + 20
= 41 + 20
= 61
24 + 37
= 37 + 24
= 37 + 23 + 1
= 60 + 1
= 61
It doesn’t matter how you do it as long as you get the right answer.
Some addition calculations …
Put the digits 7, 3 and 4 in the boxes to complete the calculation.
+
=
41
Put the digits 7, 3 and 4 in the boxes to complete the calculation.
+
=
41
Write 4 digits in the boxes.
Put one digit in each box.
+
=
56
Write 4 digits in the boxes.
Put one digit in each box.
+
=
61
Use the digits 6, 3, 4 and 9.
Put one digit in each box to make the calculation correct.
+
=
85
Use the digits 8, 5, 6 and 2.
Put one digit in each box to make the calculation correct.
+
=
93
Give two possible answers to this calculation.
+
=
800
+
Give two possible answers to this calculation.
+
=
450
+
Write the missing number in the box.
=
81
+
63
Write the missing number in the box.
=
255
+
127
Write two numbers in the empty circles so that to total of all the numbers is 2 400.
300
600
Bob has eight cards with numbers written on them. He arranges them in a square with a blank card in the middle
70
10
40
30
Each side of the square adds up to 110
Put the missing numbers in the correct boxes
Subtraction
Subtracting numbers mentally.
How would you find the difference between 67 and 42 in your head?
This means subtract or take away 42 from 67.
Sometimes we say 67 minus 42.
67 - 42
Here is one way of doing it. You could partition the numbers.
60 - 40 = 20
42 = 40 + 2
Subtract the tens
Then subtract the units
Then add the answers together
67 = 60 + 7
7 - 2 = 5
20 + 5 = 25
So 67 - 42 = 25
Did you do this?
67 – 42
67 – 40 then take away 2 equals 25
Or
67 – 2 then take away 40 equals 25
How would you find the difference
between 67 and 18 in your head?
Here are some ideas
67 take 10 gives 57 then take 8 to get 49
67 take 20 gives 47 then add 2 back to get 49
You could start with 18 and work out how much you need to get up to 67. Perhaps with a number line you have drawn, or one you have imagined in your head.
2 + 40 + 7 = 49
It doesn’t matter how you do it as long as you get the right answer.
Some subtraction calculations …
Write the missing number in the box.
=
38
─
52
Write the missing number in the box.
=
27
─
42
Put the digits 9, 2 and 4 in the boxes to complete the calculation.
─
=
15
What might the missing numbers be?
─
=
15
─
50
What might the missing numbers be?
─
=
15
─
32
What might the missing digits be?
=
593
─
32
2
5
Place Value and Number Properties Revision …
Put the digits 1, 4 and 6 in the boxes to make a number between 300 and 500.
Put the digits 2, 4, 7 and 9 in the boxes to make a number between 5 000 and 8 000.
Fill in the grid with a tick for the properties of each number.
Year 6 SATs Booster
Maths 2
Part 2 Number Investigations
You are a crack team of Mathematicians. The next slides contain a series of investigations that need open approaches such as trial and error or repeated testing to prove your theories.
Find four numbers at the four corners of a square within the grid, for example the square made by the numbers 4, 5, 14, 15. Add the diagonal numbers. What do you notice?
Find another square e.g. 45, 47, 65, 67. Add the diagonal numbers again and see what you find.
Keep finding squares across the grid. Add the diagonal numbers each time. What happens? What if you try larger squares eg. the one with the corners 78, 80, 98 and 100?
My ‘magic numbers’ are four digit numbers.
When all their digits are added together equal 6, but no digit is 0.
Can you find 10 of my ‘magic numbers’?
Each letter of the alphabet has been given a value:
A = 1p
B = 2p
C = 3p
and so on until Z = 26p.
EGG
E = 5p
G = 7p
G = 7p
Total = 19p
HAM
H = 8p
A = 1p
M = 13p
Total = 22p
Can you find a food item that comes to exactly £1?
Can you make up a menu that comes to exactly £2.50?
Imagine if you were able to turn your teacher into a frog!
A witch has told you that you will need a 24-leg potion to do this. She has provided you with an unlimited supply of the following: spiders (8 legs), lizards (4 legs) and bats (2 legs).
Unfortunately, or fortunately for your teacher, the witch can’t remember the number of each animal needed for the spell to work.
Try to find out all the possible combinations that would total 24 legs.
