in the Commands window to arrange the limits to the right of the sum symbol. If your limit entries contain longer expressions, you must put them in group (curly) brackets, for example, sum_{i=1}^{2*n} b. When formulae are imported from older versions this is done automatically. To change the spacing (gaps) between the characters choose
，令界限与总计图标右对齐。如果界限说明比较长，您就必须给它们分别加上括号，例如：sum_{i=1}^{2*n} b。在输入旧版本的公式时，它会自动加上括号。字符的间隔可以在菜单