1. 根据每组中第一题的得数，直接写出其余各题的得数。
(1) $14+27=41$
$140+270=$
$1400+2700=$
$1.4+2.7=$
$0.14+0.27=$
$\frac{14}{100}+\frac{27}{100}=$
(2) $96-25=71$
$960-250=$
$9600-2500=$
$9.6-2.5=$
$0.96-0.25=$
$\frac{96}{100}-\frac{25}{100}=$
(1) $14+27=41$
$140+270=$
$1400+2700=$
$1.4+2.7=$
$0.14+0.27=$
$\frac{14}{100}+\frac{27}{100}=$
(2) $96-25=71$
$960-250=$
$9600-2500=$
$9.6-2.5=$
$0.96-0.25=$
$\frac{96}{100}-\frac{25}{100}=$
答案：(1)
$140+270=410$
$1400+2700=4100$
$1.4+2.7=4.1$
$0.14+0.27=0.41$
$\frac{14}{100}+\frac{27}{100}=\frac{41}{100}$
(2)
$960-250=710$
$9600-2500=7100$
$9.6-2.5=7.1$
$0.96-0.25=0.71$
$\frac{96}{100}-\frac{25}{100}=\frac{71}{100}$
$140+270=410$
$1400+2700=4100$
$1.4+2.7=4.1$
$0.14+0.27=0.41$
$\frac{14}{100}+\frac{27}{100}=\frac{41}{100}$
(2)
$960-250=710$
$9600-2500=7100$
$9.6-2.5=7.1$
$0.96-0.25=0.71$
$\frac{96}{100}-\frac{25}{100}=\frac{71}{100}$
2. 先填空，再说说整数、分数和小数加减法有什么共同点。
(1) $278+64=100×(\ )+10×(\ )+1×(\ )+10×(\ )+1×(\ )$
$=100×(\ )+10×(\ )+1×(\ )$
$\frac{2}{5}+\frac{3}{8}=\frac{(\ )}{40}+\frac{(\ )}{40}=\frac{1}{40}×(\ )+\frac{1}{40}×(\ )=\frac{1}{40}×(\ )$
$6.45+3.2=1×(\ )+0.1×(\ )+0.01×(\ )+1×(\ )+0.1×(\ )$
$=1×(\ )+0.1×(\ )+0.01×(\ )$
(2) $278-64=100×(\ )+10×(\ )+1×(\ )-10×(\ )-1×(\ )$
$=100×(\ )+10×(\ )+1×(\ )$
$6.45-3.2=1×(\ )+0.1×(\ )+0.01×(\ )-1×(\ )-0.1×(\ )$
$=1×(\ )+0.1×(\ )+0.01×(\ )$
(1) $278+64=100×(\ )+10×(\ )+1×(\ )+10×(\ )+1×(\ )$
$=100×(\ )+10×(\ )+1×(\ )$
$\frac{2}{5}+\frac{3}{8}=\frac{(\ )}{40}+\frac{(\ )}{40}=\frac{1}{40}×(\ )+\frac{1}{40}×(\ )=\frac{1}{40}×(\ )$
$6.45+3.2=1×(\ )+0.1×(\ )+0.01×(\ )+1×(\ )+0.1×(\ )$
$=1×(\ )+0.1×(\ )+0.01×(\ )$
(2) $278-64=100×(\ )+10×(\ )+1×(\ )-10×(\ )-1×(\ )$
$=100×(\ )+10×(\ )+1×(\ )$
$6.45-3.2=1×(\ )+0.1×(\ )+0.01×(\ )-1×(\ )-0.1×(\ )$
$=1×(\ )+0.1×(\ )+0.01×(\ )$
答案：(1)
$278+64=100×(\boldsymbol{2})+10×(\boldsymbol{7})+1×(\boldsymbol{8})+10×(\boldsymbol{6})+1×(\boldsymbol{4})$
$=100×(\boldsymbol{3})+10×(\boldsymbol{4})+1×(\boldsymbol{2})$
$\frac{2}{5}+\frac{3}{8}=\frac{(\boldsymbol{16})}{40}+\frac{(\boldsymbol{15})}{40}=\frac{1}{40}×(\boldsymbol{16})+\frac{1}{40}×(\boldsymbol{15})=\frac{1}{40}×(\boldsymbol{31})$
$6.45+3.2=1×(\boldsymbol{6})+0.1×(\boldsymbol{4})+0.01×(\boldsymbol{5})+1×(\boldsymbol{3})+0.1×(\boldsymbol{2})$
$=1×(\boldsymbol{9})+0.1×(\boldsymbol{6})+0.01×(\boldsymbol{5})$
(2)
$278-64=100×(\boldsymbol{2})+10×(\boldsymbol{7})+1×(\boldsymbol{8})-10×(\boldsymbol{6})-1×(\boldsymbol{4})$
$=100×(\boldsymbol{2})+10×(\boldsymbol{1})+1×(\boldsymbol{4})$
$\frac{2}{5}-\frac{3}{8}=\frac{(\boldsymbol{16})}{40}-\frac{(\boldsymbol{15})}{40}=\frac{1}{40}×(\boldsymbol{16})-\frac{1}{40}×(\boldsymbol{15})=\frac{1}{40}×(\boldsymbol{1})$
$6.45-3.2=1×(\boldsymbol{6})+0.1×(\boldsymbol{4})+0.01×(\boldsymbol{5})-1×(\boldsymbol{3})-0.1×(\boldsymbol{2})$
$=1×(\boldsymbol{3})+0.1×(\boldsymbol{2})+0.01×(\boldsymbol{5})$
答：整数、分数和小数加减法的共同点是都要将相同计数单位的数相加减。
$278+64=100×(\boldsymbol{2})+10×(\boldsymbol{7})+1×(\boldsymbol{8})+10×(\boldsymbol{6})+1×(\boldsymbol{4})$
$=100×(\boldsymbol{3})+10×(\boldsymbol{4})+1×(\boldsymbol{2})$
$\frac{2}{5}+\frac{3}{8}=\frac{(\boldsymbol{16})}{40}+\frac{(\boldsymbol{15})}{40}=\frac{1}{40}×(\boldsymbol{16})+\frac{1}{40}×(\boldsymbol{15})=\frac{1}{40}×(\boldsymbol{31})$
$6.45+3.2=1×(\boldsymbol{6})+0.1×(\boldsymbol{4})+0.01×(\boldsymbol{5})+1×(\boldsymbol{3})+0.1×(\boldsymbol{2})$
$=1×(\boldsymbol{9})+0.1×(\boldsymbol{6})+0.01×(\boldsymbol{5})$
(2)
$278-64=100×(\boldsymbol{2})+10×(\boldsymbol{7})+1×(\boldsymbol{8})-10×(\boldsymbol{6})-1×(\boldsymbol{4})$
$=100×(\boldsymbol{2})+10×(\boldsymbol{1})+1×(\boldsymbol{4})$
$\frac{2}{5}-\frac{3}{8}=\frac{(\boldsymbol{16})}{40}-\frac{(\boldsymbol{15})}{40}=\frac{1}{40}×(\boldsymbol{16})-\frac{1}{40}×(\boldsymbol{15})=\frac{1}{40}×(\boldsymbol{1})$
$6.45-3.2=1×(\boldsymbol{6})+0.1×(\boldsymbol{4})+0.01×(\boldsymbol{5})-1×(\boldsymbol{3})-0.1×(\boldsymbol{2})$
$=1×(\boldsymbol{3})+0.1×(\boldsymbol{2})+0.01×(\boldsymbol{5})$
答：整数、分数和小数加减法的共同点是都要将相同计数单位的数相加减。
3. 计算下面各题，注意使计算简便。
0.88−0.03−0.17+0.12 399+245 927−402
0.88−0.03−0.17+0.12 399+245 927−402
答案：$0.88-0.03-0.17+0.12$
$=(0.88+0.12)-(0.03+0.17)$
$=1-0.2$
$=0.8$
$399+245$
$=(400-1)+245$
$=400+245-1$
$=645-1$
$=644$
$927-402$
$=927-(400+2)$
$=927-400-2$
$=527-2$
$=525$
$=(0.88+0.12)-(0.03+0.17)$
$=1-0.2$
$=0.8$
$399+245$
$=(400-1)+245$
$=400+245-1$
$=645-1$
$=644$
$927-402$
$=927-(400+2)$
$=927-400-2$
$=527-2$
$=525$