Download Maths language and number operations

Ballinagree N.S.
Language and number operations
Addition
1. We introduce the addition of 2 addends horizontally but this must lead to addition vertically
In Junior Infants
2+ 3 = is the same as
2
+3
2+3=5
We say: 2 and 3 make 5
or
2 and 3 is 5
or
2 plus 3 is 5
or
2 plus 3 equals 5
In Senior Infants and 1st. Class:
4
3
+ 2
4 + 3 + 2 = is the same as
We say: 2 plus 3 plus 4 equals
or
2 and 3 and 4 equals
2. Adding numbers without regrouping.
We introduce addition without regrouping in 1st class using cubes, lollipop sticks, abacus etc.
TU
24
+ 12
36
.
We say: Start with the units:
2 plus 4 is 6
or
2 plus 4 equals 6
or
1 plus 2 equals 3
or
1 plus 2 is 3
Answer is 36, 3 Tens and 6 Units
2 and 4 equals 6
Addition with regrouping.
We introduce addition with regrouping in 1st Class using money, cubes, abacus etc.
TU
38
+ 215
63
We say : Start with the units.
5 plus 8 is 13
13 is 1 Ten and 3 Units
Put down the 3 Units and take
ten over to the tens
1 plus 2 is 3
And 3 plus 3 is 6
Answer is 63,
6 Tens and 3 Units
Subtraction
1.
We formally introduce subtraction in 1st. Class.
Always begin from the left or from the top as appropriate.
8–3=5
2.
8
- 3
5
We say:
or
8 take away 3 is 5
8 take away 3 equals 5
Subtraction without regrouping
We introduce subtraction without regrouping using cubes, lollipop sticks in 1 st. Class.
TU
28
-13
15
3.
Always begin from the top.
We say: Start with the units
8 take away 3 is 5
2 take away 1 is 1
Answer is 15, 1 Ten and 5 Units
Subtraction with regrouping
We introduce subtraction with regrouping in 2nd Class using money, the abacus, cubes etc.
TU
2 3 13
- 1 9
1 4
Always begin from the top.
We say: 3 take away 9, I cannot do
or 9 from 3, I cannot do
Take a ten from the tens
Cross out the 3 tens
Now we have 2 tens and 13 units
13 take away 9 is 4
2 tens take away 1 is 1
Answer is 14, 1 ten and 4 units
Answer is 14, 1 ten and 4 units
Multiplication
Short Multiplication.
1.
We introduce in 3rd. Class
5 x 4 = 20
For tables we say: Five fours is 20
Children also should understand the terms “times” and “multiply”.
Long Multiplication.
2.
In 4th. Class we multiply a two – digit or three –digit number by a one or two digit number.
3 7
x 1 24 6
222
+740
962
As the “2” represents
two tens, when we
put down the zero
we have multiplied
by ten and need now
only multiply by two.
We say :
Cover the 2 (in 26)
Then 6 , 7s is 42
Put down the 2 and carry the 4
6, 3s are 18
Add in your 4, 18 + 4 is 22
Now we put down a zero
Now multiply by the 2
Two sevens are 14
Put down the 4 and carry the one
Two threes are six and one is 7
Now add
Zero plus two is two
Four plus two is 6
Seven plus two is 9
Answer is 962
Division
1.
Division is introduced in 3rd. Class
5 ÷5= 1
2.
We say:
or
five divided by five is one
how many fives in five?
Short division is introduced in 4th Class
We say :
6 [ 33712
062
How many sixes in three?
None
How many sixes in thirty-seven?
6 into 37 goes six times and
one left over
6 into 12 goes 2 times
3. Long Division is introduced in 5th Class
4. We use three steps: ESTIMATE
0214
28 [5992
-56
039
- 28
112
- 112
000
MULTIPLY
SUBTRACT (these may need to be repeated)
We say:
28 into 5 won’t go
Put up the 0
28 into 59 goes twice
Put up the 2
Put down the 56 and subtract
9 take away 6 is 3
5 take away 5 is 0
Bring down the 9
28 into 39 goes once: etc
Standardisation of some Maths Procedures in our school
It has been decided to standardise the following mathematical procedures throughout the school in
order to help children with learning difficulties.
1. Time Calculation
Addition:
1hr 35min
+ 2hrs 45min
= 3hrs. 80min (80min = 1hr 20min) so your answer is
= 4hrs 20 min
Subtraction
1hr 40min
- 0 hrs 26min
= 1 hr 14min
1 hr 40min
- 0hrs 53min
= 0hrs 47min
(we can’t take 53 min from 40
min, so we rename 1hr 40min
as 0hrs 100min)
Multiplication
Hrs
1
x
6
7 hrs
Min
13
6
78
18min
(78 min = 1hr 18min) so your answer is
Division
When dividing time, we change the hours and minutes to minutes.
1hr 27min ÷ 3 = 87min ÷3 = 29min.
0hr 100min
- 0hrs 53min
= 0hrs 47min
2. Fractions
1. Finding a fraction of a number.
(a) as per plan
3
of 72 Divide by 8 and multiply by 3
8
8 72
9
X3
27
(b) of = multiply
Find
3
of 72
8
3
72 27
x
=
8
1
1
2. Given a fraction find the whole number as per plan eg
have I?
3
= 60c
5
1
= 20c
5
5
= 100c =€1
5
3. Fractions: Addition of mixed numbers.
2
5
6
+3
2+3+
3
4
LCD = 12
5 3
+
6 4
5+
10 9
+
=
12 12
5+
19 19
7
( =1 )
12 12
12
5+1+
7
12
3
of my money is 60c. How much money
5
7
12
6+
Ans 6
7
12
4. Subtraction of mixed numbers
Method 1
2
1
3
–1
3
4
LCD =12
7 7
3 4
28 21
12 12
Ans =
7
12
5.Multipiclation of mixed numbers
Method change mixed numbers to improper fractions and then multiply.
1
1
2 x4
3
2
3
7 9 21
x =
3 2 2
1
= 10
1
2
6. Division of Fractions
6÷
1
2
6 1
÷
1 2
6 2 12
x =
= 12
1 1
1
Dividing fractions is as easy as pie
Flip the second fraction and multiply
Don’t forget to simplify
Before it gets too late to say goodbye
3.Decimals
When dealing with decimals, we will use money so that children will understand the place value of the
digits within a decimal number and learn from the physicality of the operation.
The decimal point is used to separate the pieces from the wholes.
The decimal point never moves
Eg. 2•4 + 3•76 + 1•957 = 8•117
+
2•400
3•760
1•957
8•117
It may help to put in
zeros when working out
the sum.
Tables/Number Facts
We will seek to develop an understanding of tables using a variety of techniques and games
Eg. Doubles and near doubles; dice; snakes and ladders; dominoes; playing cards; Bingo; “Quick
Draw”; “ Buzz”; worksheets;
Books eg. Table Talk, Computer software eg. Grey Ollwits, Times Tables, Maths tables games on
Scoil Net etc.
Children will be required to memorise tables in addition, subtraction, multiplication and division
Addition tables will be done formally in 1st. Class..
Subtraction tables will be done formally in 2nd Class.
Multiplication tables will be introduced as repeated addition in 3rd Class.
Division tables will be introduced as the inverse of multiplication
Language

Tables
-
Addition : 3 + 4 =7
We say; Three plus four is 7
-
Subtraction : 7 – 4 =3
We say: Seven take away four is three
-
Multiplication: 2 X 7 =14
We say two sevens fourteen
-
Division: 24 ÷ 4=6
twenty four divided by four is six
Maths Websites
www.ncca.ie
http://www.coolmath4kids.co
m/
www.sesamestreet
www.primarygames.com
www.mata.ie
www.mathsisfun.com
www.ictgames.co.uk
www.coolmath.com.
www.figurethis.org
www.mathcats.com.
www.easymaths.org.
www.bbc.co.uk/education/m
egamaths/tables.html.
www.funbrain.com/numbers.
html
http://www.mathplayground.
com/
http://www.bbc.co.uk/school
s/websites/4_11/site/numera
cy.shtml
www.scoilnet.ie