Simple calculation of 7.75 × [20 ÷ (3.24-3.07)] 7.75×【20÷（3.24－3.04）】。 Simple operation The wrong number on the top is not counted

Simple calculation of 7.75 × [20 ÷ (3.24-3.07)] 7.75×【20÷（3.24－3.04）】。 Simple operation The wrong number on the top is not counted

7.75×【20÷（3.24－3.07）】
=7.75×【20÷0.17】
=7.75×20÷0.17
=155÷0.17
=15500/17

How to divide 1.3 by 2.5

1.3÷2.5
=(1.3×4)÷(2.5×4)
=5.2÷10
=0.52

Reasonably and flexibly calculate ① 45 × 3.5 + 5.5 × 80% + 0.8 ② (717 × 19-717) × 1718 ③ 156 △ [611 × (59-14)] ④ 2.35 ± [4.75-4.5 × (0.2 + 13)]

①45×3.5+5.5×80%+0.8，=0.8×3.5+5.5×0.8+0.8，=（3.5+5.5+1）×0.8，=10×0.8，=8；②（717×19-717）×1718，=[（19-1）×717]×1718，=18×717×1718，=7；③156÷[611×（59-14）]，=116÷[611×1136]，=116÷16，=116×6，=11；④2.35÷[4.75-4.5×（0.2+13）]，=2.35÷[4.75-4.5×（15+13）]，=2.35÷[4.75-4.5×815]，=2.35÷ [4.75-2.4]，=2.35÷2.35，=1．

4920 / 24 + 38 * 50

4920/24+38*50
=205*24/24+38*50
=205+1900
=2105