（1）1.83+3.79+0.17=1.83+0.17+3.79=2+3.79=5.79（2）2.5×0.6-1.8×0.5=1.5-0.9=0.6（3）2.6+1.4×3=2.6+4.2=6.6
①1.83十3.79十0.17=（1.83十0.17）十3.79=2+3.79=5.79②2.5x0.6一1.8x0.5=1.5-0.9=0.6③2.6十1.4x3=2.6+4.2=6.8
