| ⊦ dec_i + mkDecimal(0, j) = dec_i |
⊦ dec_i + dec_j = mkDecimal(dec_i.int * 10 ^ dec_j.scale + dec_j.int * 10 ^ dec_i.scale, dec_i.scale + dec_j.scale)
⊦ mkDecimal(dec_i.int * 10 ^ mkDecimal(0, j).scale + mkDecimal(0, j).int * 10 ^ dec_i.scale, dec_i.scale + mkDecimal(0, j).scale) = dec_i
Used terms: mkDecimal(0, j), dec_i