A first-grade teacher has set up the following math workstations for students to work in pairs. Station 1: Students toss 7 two-color counters from a cup and record the addition equation represented. They repeat the process ten times. Station 2: Each student builds a tower of 8 cubes using two different colors, and then records the addition equation that the colors represent. Students then exchange towers and record the addition equation for the new towers. Station 3: Students are provided with 9 counters each. One student hides some of the counters. The other student looks at how many counters remain present and determines how many are hidden. The students then record the equation that the missing counters represent. Which of the following relationships are the students most likely exploring in the stations? Group of answer choices Spatial concepts One more and one less Benchmarking numbers Part-part-whole