Page 8 - E-Book prim 4
P. 8
Delta Modern Language Schools
Primary stage
Maths Department
Prim 4 2024-2025
Unit 2: addition and subtraction strategies
Properties of addition
Any number + 0 = the same number
1) Additive
identity Ex.: 0 + 6578 = 6578
1024 + 0 = 1024
A + 0 = 0 + A = A
Order of addends in addition
doesn’t important
We can change the place of addends
2) Commutative
Ex.: 5 + 2 = 2 + 5
A + B = B + A
Solve what in the parentheses first.
We can start by any group
Ex.: ( 5 + 2 ) + 3 = 5 + ( 2 + 3 )
3) Associative
= 2 + ( 5 + 3 ) = 10
( A + B ) + C = A + ( B + C )
= B + ( A + C )
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