SAN JOSE, Calif. – A Silicon Valley jury asked a judge for calculators Tuesday to help it determine how much Samsung Electronics owes Apple for copying key features of the iPhone and iPad.

The federal judge presiding over the patent trial granted the jury’s request Tuesday before the smartphone rivals’ lawyers delivered their closing arguments. The one-week trial is being held to determine damages for 13 of the 26 devices an earlier jury said Samsung infringed Apple’s patents in making.

Apple Inc. is demanding $380 million. Samsung counters that it only owes $52 million for using features such as “pinch-to-zoom” in the 13 older-generation products.

The jury is expected to begin deliberating Tuesday afternoon.

An earlier jury found Samsung had infringed Apple’s patents in making and selling 26 products and awarded Apple $1.05 billion. But U.S. District Judge Lucy Koh ruled that the jury miscalculated damages for 13 products. The two companies have each won and lost legal skirmishes over the past couple of years, and analysts predict continued litigation for months to come.

The current proceedings are somewhat of a warm-up for a much larger trial scheduled for March. That’s when Apple’s claims that Samsung’s newer and current products are also copying the iPhone and iPad will be considered by a jury.

Apple’s attempts to ban Samsung from selling some of the devices in question got a leg up on Monday. The U.S. Federal Circuit Court of Appeals in Washington, D.C., ordered Koh to reconsider Apple’s demands that some of the products a jury found infringed Apple’s patents be barred for sale in the United States. Koh in December turned down Apple, ruling that the company didn’t prove that consumers bought Samsung devices instead of Apple devices because of the infringement.

The appeals court told Koh to apply a different legal standard that favors Apple’s arguments. The ruling could come into play next year if Apple prevails at trial and seeks another sales ban on the newer products.

The two companies are locked in legal battles around the globe for supremacy in the more than $300 billion smartphone market.