Problems: times as many, how many more, the inverse problem
Make a number several times bigger, compare by «how many times», solve indirect problems and inverse problems. Section: Grades 2-3, "times as many", "how many more", inverse problem; price/quantity/cost tables are in another studio.
- Ukraine: grade 2
- Russia: grade 3
Guide
A studio for Ukrainian grades 2-3 (НУШ textbooks). Four problem types that are easy to mix up unless a diagram is drawn.
Making a number 3 times bigger means taking it 3 times and multiplying. Comparing by «how many times» answers «how many times as many?»: divide the bigger number by the smaller. «How many more?» is a different question: subtract.
In the indirect form the story says «6 fewer» but the unknown is the bigger number, so you add. An inverse problem swaps the unknown with one of the data. It is also a way to check an answer.
Each task has three steps: what is known, what is asked, a diagram with the answer. The last «why?» question asks you to explain the choice of operation.