Practise reading the digital clock with 3 different digital times. Each clock has a text box that can display the time textually.
Press the cursor button in the toolbar to control the tool. Look at the clocks and read out the time on both clocks. Next, calculate the time difference either orally or in writing. You can get instant feedback by clicking on the closed eye icon.
Working in pairs is also possible:
One student reads out the time difference and you discuss whether the answer is correct. The other student can reveal the correct answer. Then, the students can switch roles.