Throughout my tutoring experience, I have found that many students of all ages have difficulty writing conclusion sentences. A good activity for elementary students is to give them a topic sentence and then tell them they need to write a conclusion that expresses the SAME IDEA but use DIFFERENT WORDS. They should NOT add new information (ie details) in their conclusion. It is extremely important to give them examples.
Topic: Winter sports are lots of fun.
Conclusion: I always look forward to participating in winter sports.
Topic: Last summer, I went to Hawaii with my family.
Conclusion: I enjoyed spending time with my family in Hawaii
Here are some other topics your student can try:
Topic: Students should not wear uniforms at school.
Topic: It is important to eat a variety of fruits and vegetables if you would like to have a healthy diet.
Topic: I will never forget my first day of fourth grade.