The study could also help scientists trace back the origins of humans' mathematical skills.

The study was conducted by researchers at Harvard University Medical School and colleagues. The team taught three rhesus monkeys 26 distinct symbols, which included Arabic numerals and 16 letters. Each symbol was associated with a reward (drops of water or juice), Livescience reported.

Researchers found that monkeys quickly learnt to find the link between value of a symbol and the reward. The study subjects almost always chose the symbol with the greatest value. Monkeys were 90 percent accurate in choosing the symbol that would fetch them the largest reward.

"The monkeys want the most of whatever is out there, and this is just one of many ways to figure out the best way to get the most," Margaret Livingstone, a neuroscientist at Harvard University Medical School and lead author of the study, according to Livescience.

Next, researchers wanted to know whether monkeys could add. Researchers presented two associated symbols and a third character. To get the reward, the subjects had to add the symbols and judge whether the value was greater than the third symbol. The team found that monkeys could add the symbols and choose the greatest values.

The monkeys were then taught a different set of symbols to test whether or not they were actually conducting the additions or just memorizing the symbol pairs with the highest values. Researchers found that the subjects could apply the addition skills to the new set of symbols and obtain higher rewards, according to a report on Physorg.

"The data in my opinion are quite convincing, because it is really unlikely that the monkeys remembered each combination of symbols," says Elsa Addessi at the Institute of Cognitive Sciences and Technologies in Rome, according to New Scientist. "Maybe previous studies underestimated the addition capabilities of monkeys."

In the next part of the study, Livingstone and colleagues will test if monkeys can learn multiplication.

The study is published in the journal Proceedings of the National Academy of Sciences.

A related study had found that chickens are better at math than an average toddler.