=7.8×2.6+7.8×7.4=7.8×(2.6+7.4)=7.8×10=78
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7.8×2.6+0.78×74=0.78x26+0.78x74=0.78x(26+74)=0.78x100=78
7.8×2.6+0.78×74=7.8×2.6+7.8×7.4=7.8×(2.6+7.4)=7.8×10=78