The phrase "able to reduce the number of" is correct and usable in written English.
You can use it when discussing the capability or effectiveness of something in decreasing a quantity or amount.
Example: "The new software is able to reduce the number of errors in the data entry process significantly."
Alternatives: "capable of decreasing the number of" or "able to lessen the number of".
He and his partners were able to reduce the number of patients each saw in an hour to just four, from five or six under managed care.
Commercial stations will be able to reduce the number of locally produced hours they broadcast in exchange for an enhanced commitment to regular and updated local news.
Simply by working together, the three were able to reduce the number of times patients had to be readmitted to the hospital by 15 percent.
For just one ingredient, vanilla, its American operation was able to reduce the number of specifications and use fewer suppliers, saving $30m a year.
With more of those higher-paying customers, the airlines were able to reduce the number of cheap seats available, raising their overall revenue per flight.
Mr. Harries said it would take more time to know whether schools that now receive extra money from the state were able to reduce the number of students in their classrooms.
Health workers may be able to reduce the number of infant deaths by making regular visits before and after birth to the homes of pregnant women considered at risk.
If the company does not replace some workers and is able to reduce the number of workers that it must continue to pay, under the contract, after eliminating their jobs, the savings could be even higher, she said.
In Britain, for instance, O2 (owned by Telefónica) and Vodafone expect to be able to reduce the number of the sites that make up their networks by about 25%.
Distributive law is able to reduce the number of gates in a circuit.
Using this compression, we are able to reduce the number of possible definitions for each process node.
