MWP is more challenging than that as it requires
both precise relation reasoning about quantities and
reliable generation for diverse equation combina-
tions. Both are necessary for mathematical reason-
ing. Existing methods all consider the MWP from
a single view and thus bring certain limitations.
We argue that multiple views are required
to comprehensively solve the MWP. As shown
in Figure 1, the process of human solving in-
herently involves multiple reasoning views, i.e.,
top-down decomposition (
remaining fruits −
→
total fruits ×
→pick rate +
→
), and bottom-up
construction (
+
→pick rate ×
→total fruits −
→
remaining fruits
). Two reasoning views
are reversed in the process but consistent
in results. Meanwhile, mathematical equa-
tion can be expressed in multi-order traversal,
i.e., pre-order (
−,×,+,2,3,4,5
) and post-order
(
2,3,+,4,×,5,−
). Two sequences are quite dis-
similar in form but equivalent in logic. Two order
traversal equation corresponds exactly to the two
reasoning processes, i.e. , the pre-order equation
is a top-down reasoning view, while the post-order
can be seen as a bottom-up reasoning view.
Inspired by this, we design multi-view reason-
ing using multi-order traversal. The MWP solv-
ing is decoupled into two independent but consis-
tent views: top-down reasoning using pre-order
traversal to decompose problem from global to lo-
cal and a bottom-up process following post-order
traversal for relation construction from local to
global. Pre-order and post-order traversals should
be equivalent in math just as top-down decompo-
sition and bottom-up construction should be con-
sistent. In Figure 1, we add multi-granularity con-
trastive learning to align the intermediate expres-
sions generated by two views in the same latent
space. Through consistent alignment, two views
constrain each other and jointly learn a accurate
and complete representation for math reasoning.
Besides, math operator must conform to mathe-
matical laws (e.g., commutative law). We devise a
knowledge-enhanced augmentation to incorporate
mathematical rules into the learning process, pro-
moting multi-view reasoning more consistent with
mathematical rules.
Our contributions are threefold:
•
We treat multi-order traversal as a multi-view
reasoning process, which contains a top-down
decomposition using pre-order traversal and
a down-up construction following post-order.
Both views are necessary for MWP.
•
We introduce consistent contrastive learning
to align two views reasoning processes, fus-
ing flexible global generation and accurate
semantics-to-equation mapping. We also de-
sign an augmentation process for rules injec-
tion and understanding.
•
Extensive experiments on multiple standard
datasets show our method significantly outper-
forms existing baselines. Our method can also
generate equivalent but non-annotated math
equations, demonstrating reliable reasoning
ability behind our multi-view framework.
2 Related Work
Reliable reasoning is a necessary capability to
move towards general-purpose AI. How to achieve
human-like reasoning has been extensively re-
searched in areas such as natural language process-
ing, reinforcement learning, and robotics (Fu et al.,
2021;Zhang et al.,2021,2022a). In particular,
mathematical reasoning is an important manifesta-
tion of intelligence. Automatically solving mathe-
matical problems has been studied for a long time,
from rule-based methods (Fletcher,1985;Bakman,
2007;Yuhui et al.,2010) with hand-crafted fea-
tures and templates-based methods (Kushman et al.,
2014;Roy and Roth,2018) to deep learning meth-
ods (Wang et al.,2017;Ling et al.,2017) with
the encoder-decoder framework. The introduction
of Transformer (Vaswani et al.,2017) and pre-
trained language models (Devlin et al.,2019;Liu
et al.,2019b) greatly improves the performance
of MWPs. From the perspective of proxy tasks,
we divide the recent works into three categories:
seq2seq-based translation, seq2structure genera-
tion, and iterative relation extraction.
Seq2seq-based translation MWPs are treated
as a translation task, translating human language
into mathematical language (Liang and Zhang,
2021). Wang et al. (2017) proposed a large-scale
dataset Math23K and used the vanilla seq2seq
method (Chiang and Chen,2019). Li et al. (2019)
introduced a group attention mechanism to en-
hance seq2seq method performance. Huang et al.
(2018) used reinforcement learning to optimize
translation task. Huang et al. (2017) incorporated
semantic-parsing methods to solve MWPs. Al-
though seq2seq-based methods have made great
progress in the field, the performance of these meth-
ods is still unsatisfying, since the generation of