how would you use estimation to find the answer to 2,860 ÷ 13?
DESCRIPTION
Let’s Review Multiplication and division are inverse operations. 45 ÷ 9 = n n x 9 = 45 9 x n = 45TRANSCRIPT
How would you use estimation to find the answer
to
2,860 ÷ 13?
In this lesson you will learn how to divide
by estimating and adjusting the quotient.
Let’s ReviewLet’s ReviewMultiplication and division are inverse
operations.
45 ÷ 9 = n
n x 9 = 45
9 x n = 45
Let’s ReviewLet’s ReviewChallenging problems can be broken
into smaller parts20 x 13
20 = 2 x 10
I know that 20 is 2 times 10
I can multiply 13 x 2 and get
26
Then I can multiply 26 x 10
and get 260
26 x 10 = 260
13 x 2 = 26
20 x 13 = 260
Let’s ReviewA Common Mistake
Dividing with very small numbers
1,215 ÷ 10Running total
Quotient
1,215
608
2 -(2x10)=201,196
Let’s ReviewCore Lesson2,860 ÷ 13
Smart rounding ≈ 2,400 ÷ 12
Smart estimate ≈200
24 divides easily by 12
Let’s ReviewCore Lesson2,860 ÷ 13 This
makes sense since our smart estimate was 200
Running total Quotient
2,860
10 x 13= 130100 x 13= 1,300
200 x 13 = 2,600
-(200 x 13) = 2,600
260
20013 x 1= 1313 x 2 = 2613 x 20 = 260
-(20 x 13) =260
0
20
220
Let’s ReviewCore LessonThere are 1,716 stamps for 16 students.
How many stamps does each student get?Smart rounding ≈ 1,600 ÷ 16
Smart estimate ≈100
1,600 divides easily by 16
Let’s ReviewCore Lesson1,716 ÷ 16 This
makes sense since our smart estimate was 100
Running total Quotient
1,716
10 x 16= 160100 x 16= 1,600
-(100 x 16) = 1,600 116100
10 x 16= 160Too large5 x 16 = 80
-(5 x 16) =8036
52 x 16 = 32
-(2 x 16) =32
4 left
2
107
In this lesson you have learned how to divide
by estimating and adjusting the quotient.
Let’s ReviewGuided PracticeUse estimation and adjustment to solve 2,860 ÷ 13. Running total
Quotient
2860
Let’s ReviewExtension ActivitiesUse estimation and adjustment to solve
2,575 ÷ 23. Explain your work.
Susanna is sorting her giant button collection into boxes. She wants each box to have the same number of buttons. She has 3,920 buttons. If she has 15 boxes, how many buttons will she put in each box. Will she have any left over?
Let’s ReviewQuick Quiz
Which table shows how to divide 1,655 ÷ 15?
Running total Quotient
1,655
-(100 x 15)=1500
100
155-(10 x 15) =
150
10
5 left 110
Running total Quotient
1,655-(9 x
112)=1008112
647-(40 x 15) =
600
40
47 left 152
Running total Quotient
1,655
-(100 x 16)=1600
100
55-(10 x 5) = 50
10
5 left 110
A B C
Let’s ReviewQuick Quiz
Which table shows how to divide 1,248 ÷ 12?
Running total Quotient
1,248
-(100 x 12)=1,000
100
248-(12 x 20)
=240
10
58 left 110
Running total Quotient
1,248-(12 x
100)=1,200100
48-(12 x 4) = 48
4
0 104
Running total Quotient
1,248
-(100 x 12)=1,100
100
148-(12 x 12)=
144
10
4 left 110
A B C