`a)25xx532xx4`
`=(25xx4)xx432`
`=432xx100=43200`
`b)456xx200-456xx100`
`=456xx(200-100)`
`=456xx100=45600`
\(a,25\times432\times4=25\times4\times432=100\times432=4320\\ b,456\times200-456\times100=456\times\left(200-100\right)=456\times100=45600\)
`25 xx 432 xx 4 = (25xx4 ) xx 432 = 100 xx 432 = 43200`
`456 xx200 - 456 xx 100 = 456 xx ( 200 - 100 ) = 456 xx 100 = 45600`