7.2×1.25×1.4=9×0.8×1.25×1.4=（9×1.4）×（0.8×1.25）=12.6×1=12.6
＝8×0.9×1.25×1.4＝8×1.25×0.9×7×0.2＝10×3×0.3×7×0.2＝9×7×0.2＝12.6
