7.49-(0.56+2.49)=7.49-0.56-2.49=7.49-2.49-0.56=5-0.56=4.44
21.43-2.17-7.83+8.57=21.43+8.57-2.17-7.83=(21.43+8.57)-(2.17+7.83)=30-10=20
7.49-(0.56+2.49)=7.49-0.56-2.49=7.49-2.49-0.56=5-0.56=4.44
21.43-2.17-7.83+8.57=21.43+8.57-2.17-7.83=(21.43+8.57)-(2.17+7.83)=30-10=20