The phrase "a number of exchanges" is correct and usable in written English.
It can be used when referring to multiple interactions or transactions that have taken place.
Example: "Over the past few weeks, there have been a number of exchanges between the two companies regarding the new contract."
Alternatives: "several exchanges" or "multiple exchanges".
Fincham continued: "What happens with billings is we have a number of exchanges [of draft schedules].
From 1905 to 1910 he published a number of exchanges between himself and critics of his thesis in the Archiv.
"I'd had a number of exchanges with mainland institutions," said Mr. Sigg, who was the Swiss ambassador to China in the 1990s.
They favour an "hourglass" solution: competition among a number of exchanges and settlement firms, with a single central counterparty, so that users can net off sales and purchases.
First baseman Tino Martinez took a called third strike, turned and argued with the home plate umpire Laz Diaz, who had a number of exchanges with hitters from both teams.
In fact, it has lost market share, in large part because a number of specialist firms, which have operations on a number of exchanges, began to offer to pay for order flow.
At the end of 2012, a number of exchange executives said they were increasing efforts to reduce the problems.
In addition to Alibaba, there are now almost two hundred Chinese companies with shares listed in the United States, as well as a number of exchange-traded funds that enable U.S. investors to buy a basket of Chinese stocks.
A number of exchange-traded funds also own producers of hard assets, including s&p Global Materials (fee, 0.48% a year) and the Van Eck Market Vectors Agribusiness ETF (fee, 0.65%.) These metals and agricultural firms are cheap by historical standards and offer an inflation hedge.
Key PH domain proteins involved in signalling via PI3Ks include the phosphoinositide-dependent protein kinase 1 (proteinprotein kinase B (Akt) and a number of exchange factors for small G proteins of the Ras superfamily [ 3, 5].
The public-facing Web sites of a number of American exchanges have been hacked.
