Dame Celia Mary Hoyles, DBE, FAcSS (born 18 May 1946) is a British mathematician, educationalist and academic. She is Professor of Mathematics Education at the UCL Institute of Education.  Since January 2014, she has been President of the Institute of Mathematics and its Applications. She served as Government Chief Adviser for Mathematics from 2004 to 2007 and as Director of the National Centre for Excellence in the Teaching of Mathematics from 2007 to 2013.
In the 2004 New Year Honours, Hoyles was appointed Officer of the Order of the British Empire (OBE) 'for services to education'. In the 2014 New Year Honours, she was promoted to Dame Commander of the Order of the British Empire (DBE) in recognition of her service as Director of the National Centre for Excellence in the Teaching of Mathematics. She has been elected a Fellow of the Academy of Social Sciences (FAcSS).
In 2003, she was awarded the first Hans Freudenthal Medal by the International Commission on Mathematical Instruction in recognition of 'the outstanding contribution that [she] has made to research in the domain of technology and mathematics education'. In 2010, she was awarded the first Kavli Education Medal by the Royal Society 'in recognition of her outstanding contribution to research in mathematics education'.
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