Warm It Up
42 × 6
252
24 × 13
312
315 × 12
3,780
A student solved:
32 × 14
They found:
Did the student solve the problem correctly?
Yes. 32 × 14 = 448.
A teacher buys 18 boxes of pencils. Each box contains 24 pencils.
How many pencils did she buy?
432 pencils
68 × 7
476
47 × 26
1,222
642 × 23
14,766
A student says:
54 × 23 = 1,242
Is the student correct?
Yes.
54 × 3 = 162
54 × 20 = 1,080
1,080 + 162 = 1,242
There are 36 students attending a field trip from each of 27 classrooms.
How many students are attending altogether?
972 students
235 × 4
940
83 × 34
2,822
1,208 × 34
41,072
A student solves 72 × 34 like this:
What mistake did the student make?
The student treated the 3 as 3 instead of 30.
The second partial product should be 2,160.
Correct product: 2,448
A theater has 128 seats in each section. There are 24 sections.
How many seats are in the theater?
3,072 seats
487 × 6
2,922
126 × 45
5,670
2,456 × 48
117,888
A student says:
325 × 42 = 13,000
What did the student forget?
The student only multiplied 325 × 40 and forgot to multiply by the 2 ones.
325 × 40 = 13,000
325 × 2 = 650
Correct product: 13,650
A fundraiser sells 1,245 tickets for $18 each.
How much money did the fundraiser collect?
$22,410
1,286 × 7
9,002
284 × 67
19,028
3,684 × 57
209,988
A student says:
2,145 × 32 = 6,864
Without completely solving the problem, explain how you know the answer is unreasonable.
Since 2,145 × 30 is already more than 60,000, the product cannot be only 6,864.
Exact product: 68,640
A factory packages 3,275 pieces of candy each day for 46 days.
How many pieces of candy does the factory package?
150,650 pieces