"Deutsche Mathematik" means "German Mathematics" in English. It refers to the mathematical work and contributions made by mathematicians who were born, grew up or worked in Germany.
So, let's think of it like baking a cake. Just like how a cake has different ingredients to make it taste good, math also has different parts that work together to solve problems. Scientists from all over the world have contributed to math, but German mathematicians have made a lot of important contributions!
Many famous German mathematicians have come up with important theories that we still use today. For example, Carl Friedrich Gauss was a mathematician who figured out a lot of important truths about numbers. He helped us understand how to measure things and even helped make satellite navigation possible.
Deutsche Mathematik is important because it helps us understand the world around us better. We use math to solve problems in science, engineering, finance, and so many other areas. And by building on the work of mathematicians from different countries, we can continue to make progress and solve even bigger problems in the future.