10.1×78=（10+0.1）×78=10×78+0.1×78=780+7.8=787.8
等于(10＋0.1)×78
等于10×78＋0.1×78
等于780＋7.8
等于787.8
10.1×78= （10+0.1）X78=10X78+0.1X78=780+7.8=787.8
101乘以两位数ab=abab 10.1*7.8=787.8
