Problem children psychics

That's the problem (under the cut) caught in the book for the third class. In Ukrainian, but there everything is clear. At number 3 it. Maybe I'm really dumb, but how to solve it, I did not doper, you see, really for psychics wrote

2 Picchu



№3 *
If Che, here's the translation:
"Brother 6 ate plums and sister - 5. How many plums eaten grandmother?»



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