Thousands of schools in Nepal have reopened over a month after the country was hit by two devastating earthquakes with the magnitude measuring as high as 7.8.

Students across the country attended class on Sunday in temporary classrooms - some made out of bamboo - on school grounds.

The two major earthquakes on April 25 and May 12 killed more than 8,000 people and injured at least 20,000 people in one of the world's least developed countries.

With most school buildings damaged or unsafe, the education ministry ordered that classes be held in temporary classrooms.

Government inspectors who were sent to the schools gave green stickers for safe buildings or red stickers for damaged ones.

Al Jazeera's Harry Fawcett, reporting from the Patan Higher Secondary School in Lalitpur, near Kathmandu, said that the main building had been badly cracked by the earthquakes.

"It has a red sticker on it, meaning it will be taken down in the next few weeks. They have constructed a number of bamboo classrooms on the grounds, with the help of UNICEF and a local NGO," he said.

He added that there was a sense that the schoolchildren were "happy to be back at the school, despite what they've gone through".

Iswor Man Bajracharyan, the head of the school said that there was a general feeling of relief to be back at the school: "Today we are feeling very good because all the students have come back to school ... playing games and singing songs."

But he said it was not easy for many to readjust after the quake, despite the school opening its doors in the badly hit district.

"So many people from the village side who don't stay here in the area haven't come back from the village... It is very difficult for us to manage everything here.

He added that the school was waiting for the government to provide money to rebuild the main building.

It is estimated that more than 90 percent of schools were destroyed in the worst-hit districts of Gorkha, Sindhupalchok, and Nuwakot. Almost 24,000 classrooms were damaged or destroyed.

Nepal's government estimates reconstruction costs of $7bn, a third of the country's GDP, but with fears of corruption, it could take years to rebuild the country.