Estimation
Sandy, Mike, Melanie, and Sally each have 47 baseball cards. About how many baseball cards do they have in all?
200
9x8
72
12X10
120
Josh solves 75 x 41
He multiplies the following
70 x 40 =
70 x 1 =
5 x 1 =
What multiplication equation is he missing to find his product?
40 x 5 =
Rachel buys 4 packs of pencils. Each pack has 13 pencils. About how many pencils does she have?
40
Joan has 18 yellow balloons. Jessica has 13 times more yellow balloons than Joan. About how many yellow balloons do they have together ?
200
56X4
224
What is the product of these two numbers? 16 and 13
208
Brandon has 18 yellow balloons. Charles has 5 times the amount yellow balloons as Brandon. How many yellow balloons does Charles have?
90
Benny has saved 14 quarters from washing cars. About how many cents does Benny have ?
Any reasonable answer.
250-300
778X5
3890
How many partial products will this equation have?
124 x 6 =
3
Melanie bought 8 dozen eggs from the grocery store to bake some cakes. How many eggs did Melanie buy?
96
Mike has 3 dozen golf balls. About how many golf balls does he have
30
89X9
801
Jessica said that the partial products for 32 x 24 using the area model was:
600
40
120
80
Is this correct? Why or why not?
She is not correct because she said that 4 x 2 =80. It should be 8
There are 39 calories in a candy bar. How many calories are there in 41 candy bars?
1,599
There were a total of 16 chess matches a month. The season is played for 12 months. About many chess matches are in the season?
200
Any reasonable answer
4399X7
30,793
79X98
7,742
Brandon wanted to solve 31 x 45. He followed these steps
1. Decompose 31 and 45 in to (30 +1) and (40 + 5)
2. Multiply using the area model
- 30 x 40= 1200
- 30 x 5= 150
- 5 x 40= 200
- 1 x 5 = 5
His product was 475.
Is this correct? If not what mistake did he make? What should have been his final product?
He is not correct. He should have multiplied 40 x 1 instead of 40 x 5. This should give him a partial product of 40. His final product should have been 1,395
There are 10 children in the classroom, each child will get 4 dozen pencils. How many pencils will the teacher give out?
480