In this Grade 4 Saxon Math lesson from Chapter 2, students learn to solve addition word problems with missing addends using the "some and some more" and "part plus part equals whole" formulas. Students practice identifying the problem type, writing equations with a variable to represent the unknown addend, and using subtraction to find the missing number. The lesson builds skills in translating real-world scenarios into number sentences and checking whether answers are reasonable.
Section 1
📘 Addition Word Problems with Missing Addends
We can represent addition problems about parts adding up to a whole with this formula:
Next, you'll apply this formula to various scenarios, translating stories into equations to find the missing part.
Section 2
Missing Addend Word Problems
Jamie picked some apples, then picked 5 more to have 12 total. How many at first?
, so apples.
A class has 25 students, 12 of whom are girls. How many are boys?
, so boys.
When a story gives you the total but hides one of the parts, you can solve the mystery! Set up an addition equation with a variable for the missing number, then subtract the part you know from the total to find your answer.
Section 3
Part-Part-Whole Problems
A 24-hour day has 10 hours of light. How many hours of dark?
, so hours.
A team of 30 players has 18 on the field. How many are on the bench?
, so .
Think of a whole group made of two parts. If you know the size of the whole group and one part, you can easily find the other part by subtracting.
Section 4
Some and Some More Problems
Walter had 8 marbles and now has 17. How many more did he get?
, so .
Tamira read 6 pages, then more, totaling 13. How many more pages?
, so .
This is for stories where an amount grows. You start with 'some,' get 'some more,' and end with a total. To find the missing amount, just subtract what you started with!
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Section 1
📘 Addition Word Problems with Missing Addends
We can represent addition problems about parts adding up to a whole with this formula:
Next, you'll apply this formula to various scenarios, translating stories into equations to find the missing part.
Section 2
Missing Addend Word Problems
Jamie picked some apples, then picked 5 more to have 12 total. How many at first?
, so apples.
A class has 25 students, 12 of whom are girls. How many are boys?
, so boys.
When a story gives you the total but hides one of the parts, you can solve the mystery! Set up an addition equation with a variable for the missing number, then subtract the part you know from the total to find your answer.
Section 3
Part-Part-Whole Problems
A 24-hour day has 10 hours of light. How many hours of dark?
, so hours.
A team of 30 players has 18 on the field. How many are on the bench?
, so .
Think of a whole group made of two parts. If you know the size of the whole group and one part, you can easily find the other part by subtracting.
Section 4
Some and Some More Problems
Walter had 8 marbles and now has 17. How many more did he get?
, so .
Tamira read 6 pages, then more, totaling 13. How many more pages?
, so .
This is for stories where an amount grows. You start with 'some,' get 'some more,' and end with a total. To find the missing amount, just subtract what you started with!
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter