Evaluate results are not accurate

[JellyBrick]

Test code

import com.mpobjects.bdparsii.eval.Parser
import org.junit.Test

class MathTest {
    @Test
    fun testMathExpression() {
        println(Parser.parse("239081204214*1247981247912749").evaluate().toPlainString())
        println(Parser.parse("(70*6)/5").evaluate().toPlainString())
    }
}

Except

298368859587470504923124286
84

Result

298368859587470500000000000
420