i think of a number and add 6. my answer is 17, what number did i start with? s ums and t hings for...
TRANSCRIPT
I think of a number and add 6. My answer is 17, what number did I start with?
SUMS AND THINGS FOR PARENTS!
11Well done Chris. How did you think that through?
What can a numerate child do?
By the age of 11 they should :
have a sense of the size of number and where it fits into the number system
know by heart addition and subtraction facts to 20, multiplication and division facts to 10x10, doubles and halves, complements to 100, multiply and divide by 10 and 100
use what they know to figure out answers mentally
What can a numerate child do? (cont.)
calculate accurately and efficiently, both mentally and on paper, using a range of strategies
recognise when it is appropriate to use a calculator- and when it is not- and be able to use one effectively
explain their methods and reasoning using correct mathematical terms
judge whether their answers are reasonable and have strategies for checking them where necessary
The aim
The aim is for children to do mathematics in their heads, and if the numbers are too large, to use pencil and paper to avoid losing track. To do this children need to learn quick and efficient methods, including appropriate written methods.
All of this relies on knowing number facts to prevent the need to work out each small stage.
We want children to ask themselves:
Can I do this in my head?
Can I do this in my head using drawings or jottings to help?
Do I need to use an expanded/compact written method?
Do I need a calculator?
ADDITION AND SUBTRACTION
61 + 45 7800 – 5600
5735 + 3657 5735 + 3990
83 – 68 5002 – 4996
538 - 295 267 + 267
2.5 + 2.7 5.1 - 2.78
How do you add and subtract?
ADDITION
2 + 4 = My Mum gives me 2
sweets and my Dad gives me 4 sweets – how many do I have altogether?
8 + 6 = There are 8 people
on the train then 6 more get on. How many people are on the train now?
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76 + 47 =
76
11676
+ 40
123
+ 7
86
+10
96
+10
106
+10
116
+10
123
+7
ADDITION
ADDITION
Record steps in addition using partitioning:14 + 22
14 + 20 = 34 34+ 2 = 36or
14 + 22 10 + 20 = 30 4 + 2 = 6 80 + 6 = 36
100 + 70 + 6
+ 100 + 40 + 7
200 + 110 + 13
= 323
176 + 147 =
ADDITION
ADDITION
Have a go!
358 + 473 =
SUBTRACTION
8 – 3 = Gran baked 8 cakes.
I ate 3 – how many were left?
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2 + = 5 I have 2 cats but my
sister has 5. How many more cats does she have?
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Taking away Finding the difference
SUBTRACTION
We can do subtraction by partitioning:
38 – 14 =
38 – 10 = 2828 – 4 = 24
Imran has 43 conkers; he gives 24 away to his friends. How many does he have left?
43 – 24 =
4333
-10
23
-10
19
-4
19 conkers
SUBTRACTION
Sam has saved 93p, Amy has 55p. How much more money does Sam have than Amy?
93 – 55 =
55 60
+5
93
+3
90
+30
38p more
SUBTRACTION
8.23 – 4.55 =
3.68
8.23
8.00
5.00
4.55
+0.23
+3+0.45
SUBTRACTION
A sports stadium holds 9010 spectators. 5643 people attend a football match. How many empty seats are there?
5643
5700
6000
9010
57
+300
+3010
3367
5643 5700 9010
+ 57 +300 +3010
3367 empty seats
6000
SUBTRACTION
SUBTRACTION
Example: 639 – 424 =
600 + 30 + 9- 400 + 20 + 4
= 215
200 + 10 + 5
SUBTRACTION Example: 491 – 155 =
400 + 90 + 1
- 100 + 50 + 5
491 - 155
80
300 + 30 + 6
118 11
3 3 6
SUBTRACTION
Have a go!
Use a number line: 97 - 68 =
Use the expanded method:639 - 291 =
MULTIPLICATION
MULTIPLICATION
Each child has 2 legs. How many legs do 4 children have?
2 + 2 + 2 + 2
There are 6 eggs in a box. How many in 3 boxes?
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6 + 6 + 6
MULTIPLICATION
MULTIPLICATION
MULTIPLICATION
By the end of Key Stage 1, children are expected to know their x2, x5 and x10 tables.
By the end of Year 4, children should know all their times tables.
This knowledge is key to them being able to multiply larger numbers with written methods.
47 x 8 = x 40 78 320 56 = 376
37 x 46 =x 30 7
40 1200 280 = 14806 180 42 = 222
= 1702
MULTIPLICATION
MULTIPLICATION
MULTIPLICATION
MULTIPLICATION
Have a go at using the grid method yourself:
43 x 59 =
x 40 350 2000 150 = 2150 9 360 27 = 387
2537
How can you help?
Talk about how you do maths
Give praise and encouragement
Be positive
Ask your child to explain
Make sure maths is fun!
.
FURTHER READING
Recommended reading: ‘Maths for Mums and Dads’By Rob Eastaway and Mike AskewISBN-13: 978-0224086356