Using Trial and Error
Trial and Error:
A strategy that can be used when students are solving addition situations where the whole and one part are known, and one part is unknown.
Videos for Educators:
Important Information:
A student using trial and error to solve a problem will begin with the known part and add another part to try to find the known total. The "guess" is not random but anchored to what they already know about number.
The students will either use a concrete manipulative or counting on/all strategy to determine if their guess is too low or too high. They will then adjust their next guess based on what they discovered.
The student is developing their understanding of part-whole relationships as they adjust the missing part to find the known whole.
Key Ideas: Part-Whole Relationship, Hierarchical Inclusion, Number Conservation, Decomposing Numbers
Strategies to Support Student Learning:
encourage students to use concrete materials such as connecting cubes to solve problems
Use a variety of different problem types (join, separate, part-part-whole, compare)
begin to introduce Using a Known Fact or Using Near Doubles.
Things You Can Do In The Classroom
Games (Click Links Below)
Children work through a set of cards. For each card, children think about the number of dots they see and the whole to determine the missing part. (Lawson, pg 165)
This fun activity can be used in a small group or whole group. For this activity, place tiles of two colours in a paper bag. Tell students how many tiles there are in total and how many there are of one of the colours. Then, ask how many there are of the other colour. Children suggest answers and provide their thinking. (Lawson, pg. 166)
All games and activities located above are directly linked. Some can be found in the Alex Lawson What to Look For Resource. Page locations have been included in the description of each activity.