2.25×0.16+264×0.0225+5.2×2.25+0.225×20
=2.25×0.16+2.64×2.25+5.2×2.25+2.25×2
=2.25×（0.16+2.64+5.2+2）
=2.25×10
=22.5
故答案为：22.5．