Select the formula to be modified, install the formula editor mathtype, and double-click the formula to pop up the edit box. The formula editor is directly connected to the word document. After editing is closed, the formula effect in the document will change directly. To change the formula size, select the formula horizontally, select the size option in the selection box above, and then select Define.

In the pop-up definition size selection box, several size and data input boxes will appear as shown in the figure, with corresponding preview styles on the right.

Enter a smaller point to get a formula with a smaller font size. Directly close the formula edit box, and the formula in the word document will be reduced to the following effect.

If there may be a situation that the text does not match when modifying the document, especially by copying and pasting the formula, then double-click the formula at this time, slightly change the formula and return to the original state, so that the formula can be put back on track.