Place Value
What is the value of the 7 in 47,325?
7,000
Solve:
2,413 + 3,125
5,538
Solve:
5,648 − 2,315
3,333
Use partial sums to solve:
2,341 + 3,526
5,867
What is an algorithm?
A set of steps used to solve a problem.
Write 326,418 in expanded form
300,000 + 20,000 + 6,000 + 400 + 10 + 8
Solve
4,576 + 2,348
Answer: 6,924
Solve using the standard algorithm:
7,432 − 3,218
4,214
Use the decomposition strategy to solve:
685 − 243
442
What does it mean to unbundle and rename when subtracting?
We unbundle 1 from the place value to the left and rename it as 10 of the next smaller place value.
Compare: 64,582 o 64,528? Explain your thinking?
64,582. The first difference digit is in the tens place: 8 tens is greater than 2 tens
Solve using the standard algorithm and show where you regroup:
36,785 + 24,697
61,482
Solve and show where you unbundle and rename:
6,384 − 2,475
3,909
A student solved an addition problem like this:
4,000 + 2,000 = 6,000
500 + 300 = 800
60 + 20 = 80
7 + 5 = 12
6,000 + 800 + 80 + 12 = 6,892
What strategy did the student use?
Partial sums.
Put these steps for subtracting multi-digit numbers in the correct order:
A. Unbundle and rename if needed.
B. Line up the numbers by place value.
C. Subtract.
D. Start with the ones place.
E. Ask, “Can I subtract?”
B → D → E → A → C