Students have been exploring the concepts of measurement for years prior to Grade 3. In Grade 2, students found the mass of objects in either kilograms or grams by reading scales. In this chapter, students will be introduced to liters as a means of measuring liquids. The units of measurement for both mass and volume are explored further to increase the awareness of the smaller units, where students will be taught to convert from one to another.
The use of practical, hands-on activities in this chapter is important for students to visualize the mass and volume of various items. Students will benefit from hands-on exploration with mathematical tools such as scales, beakers, bottles, and containers, to solidify their understanding. This is also essential to the skill of estimation. In this chapter, students will learn to estimate both mass and volume, and make comparisons between their estimates and the actual measure. Estimation is encouraged for students to check their answers and their reasonableness.
In order to solve word problems on measurement, students need to be proficient in conversions between the units of measurements of grams and kilograms, and liters and milliliters. Using bar models allows students to think about how the given information in a problem is related. Students have been taught to choose the correct operation to solve word problems involving part-whole (in addition and subtraction), adding on, taking away, comparing, multiplying, and dividing. This understanding will lead students to find a solution for any one-step word problem. Students will be encouraged to draw models for all the problems to determine which operation to use.