【简答题】
某建筑首层室内地面<img class="kfformula" src="data:image/png;base64,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" data-latex="\pm 0.000"/>的绝对高程为45.300m,室外地面设计高程为-1.500m,则室外地面的绝对高程为[填空(1)]m