Previously, we created an application that helped us get insights into the implementation of a neural network image recognition program using the TensorFlow model for mobile devices. Now, we will create another application that uses the concept of a neural network and Keras for an image recognition program of handwritten digits. In this section, we will create an application for a handwritten digit recognition solution on mobile devices using Keras. Then, we will convert this Keras model into a Core ML model and use it to build an iOS mobile application. Let's start by introducing you to Keras.