1 练习六第1题答案
60+255+40
=60+40+255
=100+255
=355
282+41+159
=282+(41+159)
=282+200
=482
548+52+468
=600+468
=1068
=500
800-138-162
=800- (138+162)
=800-300
=500
672-36-64
=672- (36+64)
=672 -100
=572
672-36+64
=636+64
=700
13+46+55+54+87
= (13+87)+(46+54)+55
=100+100+55
=255
5+137+45+63+50
= (5-1-45)+(137+63)+50
=50+200+50
= (50+50)+200
=300
2 练习六第2题答案
225+328+175=728(元)
3 练习六第3题答案
2000 - 416 - 284
=2000-(416+284)
=1300（米）
4 练习六第4题答案
1+2+3+4+5+6+7+8+9+ 10 =(1+10) ×10÷2=55(根)
5 练习六第5题答案
(从上到下)107 104 106 38