【参考答案】
1、[4+(3/8)]+2.25+[5+(5/8)]+[7+(3/4)]
=4+5+(3/8)+(5/8)+2.25+7.75
=9+1+10
=20
2、53又十一分之六-十六分之七分之四+十六又十一分之五
3、[2+(3/7)]+[3+(5/9)]-[3+(3/7)]+[1+(4/9)]
=(2+3+1-3)+(3/7)-(3/7)+(5/9)+(4/9)
=3+1
=4
4、(4/5)+[9+(4/5)]+[99+(4/5)]+[999+(4/5)]+[9999+(4/5)]
=9+99+999+9999+(4/5)×5
=9+99+999+9999+4
=10+100+1000+10000
=11110
20
五十四又七分之三
4
11110