Too many students are not getting the basic education and life skills they need to succeed when they leave school, say two global organisations.
It's bad enough that 263 million children and adolescents are out of school around the world through poverty, wars, disasters and inequality.
But there are over 300 million more who do sit in a classroom every day - and are still being failed.
They are the children who are in school but not learning. Their inadequate education will leave them behind when it comes to passing exams, getting a job and taking their place in society.
Two organisations have highlighted the global learning crisis that is leaving huge numbers of young people without the basic education and life skills they need to read, write, think for themselves, understand their rights or become productive citizens.
The World Bank warned: "Even if they attend school, many leave without the skills for calculating the correct change from a transaction, reading a doctor’s instructions or interpreting a campaign promise - let alone building a fulfilling career or educating their children."
The findings of the World Bank and UNESCO in the past few days echo the warning of a learning crisis from the Education Commission last year.
Launching the Learning Generation report at the United Nations General Assembly, it said that 825 million children in developing countries - half of all the children in the world - will not get the basic secondary-level skills they need for the jobs market.
The World Bank's World Development Report 2018 on education said yesterday that - even after several years in school - millions of children cannot read, write or do basic mathematics.
"This learning crisis is widening social gaps instead of narrowing them," it said. "Young students who are already disadvantaged by poverty, conflict, gender or disability reach young adulthood without even the most basic life skills."
World Bank Group President Jim Yong Kim added: “This learning crisis is a moral and economic crisis. When delivered well, education promises young people employment, better earnings, good health and a life without poverty.
"For communities, education spurs innovation, strengthens institutions and fosters social cohesion. But these benefits depend on learning - and schooling without learning is a wasted opportunity and a great injustice."
The World Bank said teachers often lack the skills or motivation to be effective and added that many teachers are not well educated themselves. It said talented people should be recruited and teachers need better training.
The report also said that when countries and their leaders make “learning for all” a national priority, education standards can improve dramatically. It cited Vietnam, Peru and Tonga among examples of that.
It said the learning crisis begins early and called for day care centres for very young children and preschool programmes for those aged three to six.
It said that would "enhance the nurturing and protection of children to improve cognitive and socio-emotional skills in the short run, as well as education and labour market outcomes later in life".
A Theirworld scorecard published earlier this month called for countries to spend 10% of their education budgets on pre-primary - a move backed by UNICEF last week.
UNESCO's new statistics on learning revealed that more than 617 million children and adolescents - that's six in 10 - are not achieving minimum proficiency levels in reading and mathematics.
In sub-Saharan Africa, 88% of children and adolescents will enter adulthood without a basic proficiency in reading. And in central and southern Asia, 81% are not reaching an adequate level in literacy, said the agency.
“The figures are staggering both in terms of the waste of human potential and for the prospects of achieving sustainable development,” says Silvia Montoya Director of UNESCO Institute of Statistics.