Class 3 · Mathematics
Addition and subtraction with carrying
📘 Chapter notes
The key ideas of this chapter, answered through the six guiding questions. Read them with your textbook.
1What am I looking at?
Answer: Adding and subtracting 3-digit numbers with regrouping.
2What are its main parts or ideas?
Answer: Carry when a column adds to 10 or more; borrow from the next column when the top digit is smaller.
3How does it work?
Answer: Line up the numbers by place, start with ones, write the ones digit and carry the tens to the next column.
4Why is it important?
Answer: Needed for bills, scores and measurements.
5What happens if something changes?
Answer: Estimating first (round to the nearest 10 or 100) shows whether an answer is sensible.
6What should I remember for the exam?
Answer: Column addition and subtraction, word problems and checking with the inverse operation.