41.2×7.6+57.7×2.4+2.4×83.5=41.2×7.6+（57.7+83.5）×2.4=41.2×7.6+141.2×2.4=41.2×7.6+（100+41.2）×2.4=41.2×7.6+100×2.4+41.2×2.4=41.2×（7.6+2.4）+240=41.2×10+240=412+240=652
