a) \( 700+\ldots=1000 \)

To solve \( 700 + \ldots = 1000 \), we need to find the missing number. Simply subtract 700 from 1000 which gives us \( 1000 - 700 = 300 \). So, you can fill in the blank with \( 300 \) to complete the equation. When you’re adding numbers, it’s often helpful to visualize the relationship between them. For instance, here you can think of 700 as a big chunk, and 1000 as a target you want to hit. Finding that missing piece can be as satisfying as completing a puzzle!