The looking-back stage is rarely observed in students' problem solving in spite of its recognized importance. The importance of this stage is attributed to practices of engagement with queries on verification of the obtained solution(s), comparative consideration of alternative solutions, and formulation of implications for future problem solving. We refer to such practices as "looking-back practices." In the present study we explored the hypothesis that the looking-back practices can be evoked in small-group classroom discussions of controversial worked-out solutions to word problems. Such tasks are known as Who-Is-Right tasks. The data consisted of audio- and videotapes of six small groups of high-school students working on a Who-Is-Right task in the context of percentage. The data analysis, informed by a discursively-oriented perspective on problem solving, attended to strategies, dialogical moves and mathematical resources enacted by the students towards attempted agreement as to which of the solutions should be endorsed and why. The findings imply that Who-Is-Right tasks have undeniable potential for supporting collective looking-back practices. In addition, the study contributes to the literature on enactment of mathematical resources in problem-solving discourse and on patterns of students' dialogic participation in small-group problem solving.