Math · Addition

Properties of Addition
Commutative, Associative & Identity with Examples

Learn the 5 properties of addition with examples: commutative, associative, identity, inverse and distributive. For elementary and middle school with exercises.

⚡ RESPUESTA RÁPIDA

The 5 properties of addition: 1) Commutative: a+b=b+a. 2) Associative: (a+b)+c=a+(b+c). 3) Identity: a+0=a. 4) Inverse: a+(-a)=0. 5) Distributive: a×(b+c)=ab+ac.

The 5 Properties — With Examples

Commutative Property: a + b = b + a

Order doesn't matter. 3+5 = 5+3 = 8. Useful for mental math.

Associative Property: (a+b)+c = a+(b+c)

Grouping doesn't matter. (2+8)+5 = 2+(8+5) = 15. Group numbers that make 10.

Identity Property: a + 0 = a

Adding zero doesn't change the number. 7+0=7. Zero is the additive identity.

Inverse Property: a + (-a) = 0

Every number plus its opposite equals zero. 5+(-5)=0.

Distributive Property: a×(b+c) = ab+ac

3×(4+5) = 3×4+3×5 = 27. Connects addition and multiplication.

Identify the Property — 8 Exercises

7+3=3+7
Commutative
(2+8)+5=2+(8+5)
Associative
15+0=15
Identity
(-8)+8=0
Inverse
4×(3+7)=12+28
Distributive
a+b=b+a
Commutative
(x+y)+z=x+(y+z)
Associative
n+0=n
Identity

These properties also apply in algebra. Visit propiedades de la suma for the Spanish version.

Real-World Applications

Commutative — Grocery Shopping

Adding $12 + $8 or $8 + $12 gives the same total of $20. Order of purchase doesn't change the total.

Associative — Mental Math Trick

47+38+62: regroup as (47+53)+38=100+38=138 instead of 47+38+62 in order.

Identity — Bank Balance

Depositing $0 to a $500 account: $500+$0=$500. Balance unchanged.

15 Practice Exercises

8+5=5+?
8 (comm.)
(3+7)+4=3+(7+?)
4 (assoc.)
15+0
15 (identity)
(-9)+9
0 (inverse)
a+b=b+?
a
(x+y)+z=x+(y+?)
z
n+0
n
(-15)+15
0
47+53+28=100+?
28=128
25+87+75=(25+75)+?
87=187
a+0=?
a
n+(-n)=?
0
b+c=c+?
b
0+x
x
(1+2)+3=1+(2+?)
3

Preguntas Frecuentes

Do these properties work with decimals and fractions?

Yes, all properties of addition apply to any real number including decimals, fractions and negative numbers.

Is subtraction commutative?

No. 10−3=7 but 3−10=−7. Subtraction is NOT commutative. Only addition and multiplication have the commutative property.

Using Properties to Solve Problems Faster

1
Add 47 + 38 + 53 fasterCommutative: reorder → 47+53+38. Associative: (47+53)+38=100+38=138. Much easier!
2
Add 99 + 67 using inverse trick99=(100−1). So: 100+67−1=166. Faster than adding 99+67 directly.
3
Multiply 6×(200+50+3) using distributive6×200+6×50+6×3=1,200+300+18=1,518. That is how you multiply 6×253 mentally.

Properties in Algebra

Simplify 3x+5+2x+1

Commutative: reorder → 3x+2x+5+1. Associative: (3x+2x)+(5+1)=5x+6.

Expand 4(x+3)

Distributive: 4x+4×3=4x+12. This is the foundation of algebra.

20 More Exercises

7+3=3+?
7
(2+8)+5=2+(8+?)
5
15+0=?
15
(-9)+9=?
0
a+b=b+?
a
n+0=?
n
(x+y)+z=x+(y+?)
z
(-15)+15=?
0
47+53+28
128
25+87+75
187
99+45
144
198+76
274
35+67+65
167
5×(20+4)
120
3×(100+7)
321
a×(b+c)
ab+ac

Preguntas Frecuentes

Does the commutative property work for subtraction?

No. 8−3=5 but 3−8=−5. Only addition and multiplication are commutative.

Why is zero called the additive identity?

Because adding it to any number leaves the number unchanged — it does not alter the identity of the number. 7+0=7, x+0=x always.

Do these properties work with negative numbers and fractions?

Yes. All properties of addition apply to any real number: integers, decimals, fractions, negatives and even irrational numbers like π.

Also useful

The 4 Properties

Commutative

a+b = b+a. Order does not change the sum. 5+3 = 3+5 = 8.

Associative

(a+b)+c = a+(b+c). Grouping does not matter.

Identity (neutral element)

a+0 = a. Adding zero does not change the number.

Additive Inverse

a+(−a) = 0. Every number has an opposite that cancels it.

16 Exercises

Commutative: a+b=b+a
3+5=5+3=8
Associative: (a+b)+c=a+(b+c)
(2+3)+4=9
Identity: a+0=a
7+0=7
Inverse: a+(−a)=0
5+(−5)=0
45+37
82
128+295
423
1/3+1/4
7/12
2.5+3.7
6.2
(−4)+(−7)
−11
(−5)+(+8)
3
Sum 1 to 10
55
Sum 1 to 100
5,050
x+0=x always?
Yes (identity)
7+(−7)=?
0 (inverse)
Perimeter 5+7+9
21
$45+$38+$17
$100

These properties are not just abstract rules — they explain why calculations work. The commutative property lets you reorder to add easier numbers first. The associative property lets you group numbers strategically.

25+(75+38)
138 (regroup 25+75 first)
0.5+0.3+0.2+0
1.0 (identity)
(−7)+7
0 (inverse)
38+47+62+53
200 (group: 38+62, 47+53)
x+(−x)
0 always
Sum: 1+3+5+7+9
25 (5 odd numbers)
Is a−b=b−a?
No (subtraction NOT commutative)
(a+b)² vs a²+b²
(a+b)²=a²+2ab+b²
a+b+c in any order
Same result (commutative+associative)
Bank: +$500+(−$200)
$300 net
Temperature: −5+8+2
5°C
Proof: 99+1=100
Use identity/complement

The commutative and associative properties together let you rearrange and regroup numbers to make calculation easier. When adding a list of numbers, always look for pairs that make nice round numbers: 38+62=100, 47+53=100.

Aplica commutativa: 97+148+3
148+3+97=248 (fácil)
Aplica asociativa: 25+(75+38)
(25+75)+38=138
¿−7+7=?
0 (elemento inverso)
x+(−x)=0 siempre
Suma: 1+2+3+...+100
5,050 (Gauss)
Sustracción: ¿es conmutativa?
No: 8−3≠3−8
(a+b)² ≠ a²+b² — ¿por qué?
Falta el término 2ab
Completa: ?+0=17
17

La suma de 1 a 100 = 5,050 fue calculada por Gauss de niño emparejando: 1+100=101, 2+99=101... hay 50 pares. 50×101=5,050. La propiedad asociativa hace este tipo de reagrupamiento posible.

Suma eficiente: 18+27+82+73
200 (18+82=100, 27+73=100)
Propiedad clausura: suma de enteros es...
Siempre entero
a+(b−c)=a+b−c: ¿propiedad?
Distributiva del signo
¿(a+b)+c=a+(b+c) para fracciones?
Sí, siempre
Suma: 1/3+1/6+1/2
1
Suma tres negativos: −4+(−6)+(−3)
−13
Neutro aditivo
0
Inverso aditivo de 3/4
−3/4

La propiedad clausura garantiza que la suma de dos números del mismo conjunto da otro número del mismo conjunto. Naturales+Naturales=Natural. Enteros+Enteros=Entero. Reales+Reales=Real. Pero √2+√2=2√2 (irracional+irracional puede ser racional).

Properties of Addition — With Examples and Exercises

Commutative: a+b=b+a   3+5=5+3=8
Associative: (a+b)+c=a+(b+c)   (2+3)+4=2+(3+4)=9
Identity: a+0=a   7+0=7
Inverse: a+(−a)=0   5+(−5)=0

18 Exercises Solved

7+9=? and 9+7=?
Both=16 (commutative)
(3+4)+5=3+(4+5)?
Yes=12 (associative)
25+0=?
25 (identity)
−8+8=?
0 (inverse)
Reorder to simplify: 47+38+53
(47+53)+38=100+38=138
17+29+13
(17+13)+29=59
a+b+c=c+b+a?
Yes (commutative)
(x+3)+7=x+?
x+10
Additive inverse of −4
4
Additive inverse of 2/3
−2/3
Is subtraction commutative?
No: 5−3≠3−5
(1.2+3.8)+6.5
11.5
(−3)+(−5)+(+8)
0
Simplify: x+0
x
Identity element of addition
0
Use associative: 125+346+75
125+75+346=200+346=546
a+(b−a)=?
b
Is 0 its own additive inverse?
Yes: 0+0=0

The commutative and associative properties let you reorder and regroup numbers to simplify mental math. Always look for pairs that sum to 10, 100, or 1000 first — this is the key to fast addition.

¿También estudias? 🇬🇧 Inglés gratis 📜 Historia gratis 🎯 Simulador COMIPEMS