1、723-(521+504)÷25
=723-1025÷25
=723-41
=682
2、(39-21)×(396÷6)
=18×66
=1188
3、507÷13×63+498
=39×63+498
=2457+498
=2955
4、[37-(7+6)] ×30
=〔37-13〕×30
=24×30
=720
1、723-(521+504)÷25
=723-1025÷25
=723-41
=682
2、(39-21)×(396÷6)
=18×66
=1188
3、507÷13×63+498
=39×63+498
=2457+498
=2955
4、[37-(7+6)] ×30
=〔37-13〕×30
=24×30
=720