math-nli: Output if sentence 2 Entails statement 1 or Contradicts statement 1 - 
sentence 1: Sandra had some Pen. Bertha gave him 5 more. Now Sandra has 28 Pen. 
sentence 2:  Sandra had 21 pens initially.
<equate> (28 - 5, 21)
Sandra had some Pen. Bertha gave him 5 more. Now Sandra has 28 Pen. 
 Sandra had 21 pens initially.