2-Digit Mental Mathematics

Strand: Number
Outcomes: 6 and 7

Step 4: Assess Student Learning

Guiding Questions

Look back at what you determined as acceptable evidence in Step 2.
What are the most appropriate methods and activities for assessing student learning?
How will I align my assessment strategies with my teaching strategies?

Sample Assessment Tasks

In addition to ongoing assessment throughout the lessons, consider the following sample activities to evaluate students' learning at key milestones. Suggestions are given for assessing all students as a class or in groups, individual students in need of further evaluation, and individual or groups of students in a variety of contexts.

A. Whole Class/Group Assessment

Examples of Group Assessment

B. One-on-One Assessment

Ask the student to solve 24 + 32 using mental mathematics and tell you how he or she figured out the answer.
Use the following accommodations, if necessary:
- Prompt the student to use and explain the left-to-right strategy.
- Have the student use ten bars and unit cubes to show his or her thinking.
Ask the student to solve 19 + 28 using mental mathematics and tell you how he or she figured out the answer.
Use the following accommodations, if necessary:
- Prompt the student to use and explain the strategy of going to the nearest 10 in one of the addends and compensating.
- Have the student use ten bars and unit cubes or written numbers to show his or her thinking.
Ask the student to solve 43 – 29 using mental mathematics and tell you how he or she figured out the answer.
Use the following accommodations, if necessary:
- Prompt the student to use and explain the strategy of going to the nearest 10 (in the subtrahend) and then compensating.
- Have the student use drawings or written numbers to show his or her thinking.
Ask the student to solve 43 – 37 using mental mathematics and tell you how he or she figured out the answer.
Use the following accommodations, if necessary:
- Prompt the student to use and explain the strategy of thinking of addition in order to subtract.
- Have the student use drawings or written numbers to show his or her thinking.
Ask the student to solve 19 + 20 using mental mathematics and tell you how he or she figured out the answer.
Use the following accommodations, if necessary:
- Prompt the student to use and explain how doubling a number could help solve this problem.
- Have the student use ten bars and unit cubes, diagrams or numbers to show his or her thinking.
Ask the student to solve 22 – 11 using mental mathematics and tell you how he or she figured out the answer.
Use the following accommodations, if necessary:
- Prompt the student to use and explain how thinking of doubling could help him or her solve this problem.
- Have the student use ten bars and unit cubes to show their thinking.

C. Applied Learning

Everyday experiences provide frequent opportunities to practise and perform mental mathematics calculations. Adding up a bill for purchases at a store or calculating distances in a car trip are just two examples where mental mathematics is a good choice for figuring out an answer. Games can provide further opportunities to practise calculations. Teachers can encourage mental mathematics by:

creating experiences that simulate shopping
having students participate in fundraisers, such as book or bake sales where shoppers need to add together purchases and make change, especially where items are selling for small amounts (under 50 cents)
providing opportunities to play games that involve mental mathematics
challenging students to make up their own games that involve mental mathematics
introducing students to the online game "Ghostblasters" that students can play against each other to practise 2-digit mental subtraction: http://resources.oswego.org/games/Ghostblasters3/ghostsub3.html.

Related Resources

Assessment in the Mathematics