Mark Twain left school when he was twelve. He had little school education. In spite of (尽管) this, he became the most famous writer of his time. He made millions of dollars by writing. His real name was Samuel Langhorne Clemens, but he is better known all over the world as Mark Twain, his pen-name.

    Mark Twain was born in 1835 and he was not a healthy baby. In fact, he was not expected to live through the first winter. But with his mother's tender care, he managed to survive. As a boy, he caused much trouble for his parents. He used to play jokes on all of his friends and neighbors. He didn't like to go to school, and he constantly ran away from home. He always went in the direction of the nearby Mississippi (密西西比河). He was nearly drowned (淹死) nine times.

    After his father's death in 1847, Mark twain began to work for a printer, who only provided him with food and clothing. Then, he worked as a printer, a river-boat pilot and later joined the army. But shortly after that he became a miner. During this period, he started to write short stories. Afterwards he became a full-time writer.

    In 1870, Mark Twain got married. In the years that followed he wrote many books including Tom Sawyer in 1876, and Huckleberry Finn in 1884, which made him famous, and brought him a great fortune (财富).

    Unfortunately, Mark Twain got into debts in bad investments (投资) and he had to write large numbers of stories to pay these debts. In 1904, his wife died, and then three of their children passed away.

    At the age of 70, his hair was completely white. He bought many white suits and neckties. He wore nothing but white from head to foot until his death on April 21, 1910.

能简算的要用简便方法计算.

$3.82$ －6.3÷0.7×0.15＝（   ）