A formative assessment/examination is given during a course to determine how effective the students are learning from the material provided - in other words: a mid-course or mid-term test. These types of assessments are performed to measure the students’ level of knowledge mid term/course. Formative assessments are more often than not low-stakes, where the main purpose is to gain insight into what parts of the material the students may struggle with and what parts you need to focus on to help them reach the curriculum's requirements for passing the final examination.
A summative assessment/examination is used to measure the students’ learning and reaction to what was taught after a specific period; what can also be referred to as a final examination at the end of a course or term. Similar to the formative assessment/examination, it’s an evaluative device to measure the student’s knowledge in a particular subject/domain and to grade /score it. However, whereas formative assessment is usually low-stakes, summative assessment is often high-stakes (a test with important consequences for the test taker).