The phrase "an about equal number" is not correct in standard written English.
It is an awkward construction and should be rephrased for clarity.
Example: "There were an about equal number of participants from both groups."
Alternatives: "approximately the same number" or "roughly equal number".
They met an about equal number of ethnic Tuareg rebels, who may have been aided by jihadists.On May 21st the soldiers lobbed shells over the heads of African and French troops stationed at an international base.
Other uitlanders produced a counter-petition in which an about equal number affirmed their satisfaction with Kruger's government.
Most of the paralogous pairs (~80%) are made by enzymes performing exactly the same reaction and the remaining fraction is formed by an about equal number of paralogous enzymes with no functional overlap (~10%) and of paralogous enzymes with a partial functional overlap (~10%).
When the group of 300 subjects was taken as a whole, the distribution of the difference score was approximately normal, indicating there was about equal number of higher ratings and lower ratings under each method.
About equal number was sent to all the 36 states of the federation including the federal capital territory Abuja.
PITAC was a group comprising about equal numbers of academics and representatives of the technology industry, and the Cyber Security Subcommittee, which prepared the report, was chaired by Tom Leighton, MIT prof and Akamai cofounder.
And unlike traditional computer games, which are played mostly by young men, leisure games draw women and men in about equal numbers across a broad range of age groups.
A candidate's endorsement of Clinton was a wash, the poll found, with about equal numbers of voters saying they would be more or less likely to vote for a candidate who had backed her.
A total of 727 mice, with about equal numbers of male and female mice, were used to determine the effect of gender on HCC formation (supplementary material Table S1A and B).
Under the presidency of Prof. Michael Foster a large body of physiologists attended in about equal numbers from the east and west of the Atlantic.
Despite the fact that it was easily the coldest, windiest day I've experienced in my year of living in Los Angeles, there was already a sizable crowd on the street, consisting in about equal numbers of both Star Wars fans, as well as members of the media who were there to interview them about being Star Wars fans.
