Simply click the fill-in-the-blank tool, draw a box on the slide, and then click "+ add acceptable answer". Add one or many acceptable answers and any point value you want to assign. Then click back on to the slide (it will automatically save).
Important note: You do NOT need to have an 'acceptable answer'. Instead, you can use this tool as a place for students to type in their responses. Fill in the blank is NOT sensitive to capitalization meaning students can enter the answer as "NO" or "no" and still receive credit.