9.36÷1.2×9.9+0.78=9.6÷1.2X9.9-0.24÷1.2X9.9+0.78=8X9.9-0.2X9.9+0.78=8X10-8X0.1-1.98+0.78=80-0.8-1.2=80-2=78
从左到右死算真的很简单