resuelve: números enteros

. Realiza las siguientes operaciones:

Ejemplo: (+5) + ( –9) – (–3) – (+7)  =  +5 – 9 + 3 – 7  =  8 – 16 =  –8                                         

a)     (–3) + (+10) – (–5) + (+4) =

b)    (+15) – (–7) + (–10) + (+13) =

c)     (+10) + (–16) – (–3) – (+20) =

d)    (–3) + (–2) + (+18) – (13) =

e)     (–5) – (+12) + (–3) + (–10) =

f)     (+7) – (–18) – (+10) + (–15) =