Question

if a= -20cm, b=15cm and c=10 verify that :
a+(b+c) = (a+b)+ c​

Answer 1

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a+(b+c) = (a+b)+ c

20 + (15 + 10 ) = (20 + 15 ) + 10

20+(25)=(35)+10

20+25=35+10

45=45