列竖式计算,带“★”要验算.679+228= ; 63÷7= ;★1002﹣789= ; 627﹣459= ; 46÷8= ;★368+534= .
.
=
1990×2.8+199×51+1.99×2100.
524﹣(124﹣87)
94×56.87+94×43.48+6×100.35.