Traditional GCSE grades of A*-G are to be scrapped and replaced with a numbered scale under radical reforms of the exam system.
Pupils will now be marked from one to nine - with nine the highest mark available.
Debi Edward reports:
Details of new GCSEs in English and Maths - due to be taught in schools from September 2015 - were also unveiled by the Department of Education today.
The Department for Education hailed the new qualifications as more "challenging, ambitious and rigorous".
Under the plans for the new English course, teenagers will have to study study at least 15 poems at GCSE, including works by authors such as Wordsworth, Byron and Keats.
In future, pupils will be required to learn poems by no fewer than five poets - and to study 300 lines of poetry at a minimum.
Youngsters will also be told they must "broaden their knowledge of literature" and read widely to prepare for unseen texts in exam papers.
The new Maths GCSE will also be "bigger in content", and more challenging and will include new sections on ratio, proportion and rate of change.
Students will also have to learn key formulae such as how to calculate the area of a triangle off by heart.
Education Secretary Michael Gove said the new GCSEs in English and maths "set higher expectations".
In a written ministerial statement, Mr Gove said: "They demand more from all students and provide further challenge for those aiming to achieve top grades".
Exam regulator Ofqual said the move to a numerical grading system will signal that the revamped GCSEs are a new qualification and would make it easier to distinguish between the brightest students.
The regulator said that in some subjects such as maths and science, high numbers of pupils achieve A* and A grades which makes it difficult to pick out the top students.
Chief regulator Glenys Stacey said that in these cases "you then begin to question whether the qualification is doing its job in differentiating sufficiently your most able students."
However, students and teachers have expressed concern over new reforms and the potential impact it may have on future employers.
Georgia Urmson, who is preparing to take her GCSEs, said employers may favour students who take exams under the new system because of the perception that exams are more challenging.
The 16-year-old also suggested that taking one exam at the end of the year is unfair on students who find exams difficult but are intelligent in other aspects of learning.
The Headteacher of one school said changes to the system could prove "detrimental" to children who struggle under pressure.
Andrew Keeley, who leads St Chad's school in Liverpool, said he believes one off exams are poor for students, and that a modular system combined with coursework enables students with different abilities to succeed.
The plan to change the grading system to numbers could cause a significant period of confusion, which may be damaging to students and employers.
The Association of School and College Leaders (ASCL) gave a "cautious welcome" to the reforms to GCSE exams.
The organisation said a concerted effort needed to made to communicate the changes to pupils, parents, and employers well before they come into effect to avoid "mass confusion".
ASCL Deputy General Secretary Malcolm Trobe said: