3.8*99
=3.8×100-3.8
=380-3.8
=376.2
101*五分之四—五分之四
=(101-1)×4/5
=100×4/5
=80
七十四分之三*75
=3/74×(74+1)
=3/74×74+3/74
=3又3/74
十七分之三*36+15除以三分之十七
=3/17×36+15×3/17
=3/17×(36+15)
=3/17×51
=9
3.8*99
=3.8×100-3.8
=380-3.8
=376.2
101*五分之四—五分之四
=(101-1)×4/5
=100×4/5
=80
七十四分之三*75
=3/74×(74+1)
=3/74×74+3/74
=3又3/74
十七分之三*36+15除以三分之十七
=3/17×36+15×3/17
=3/17×(36+15)
=3/17×51
=9