par Maya Royster Il y a 2 années
131
Plus de détails
1)There was 3/4 of a pie in the refrigerator. John ate 2/3 of the left over pie. How much pie did he eat?
He ate 1/2 of the whole pie
2) Three-fourths of the class are girls. Two-thirds of the girls have black hair. What fraction of the class is female and dark haired?
1/4+1/4=2/4=1/2
1/2 of the class are girls and have black hair.
A set of marbles can be divided in equal shares among 2, 3, 4, 5, or 6 children with no marbles left over, what is the least number of marbles this set could have?
2:2,4,6,8,10….. 60
3: 3,6,9,12,15,18…..60
4:4,8,12,16……60
5: 5,10,15,20,25…..60
6: 6,12,18,24,30….60
The least number of marbles this set could have is 60
Problem solving example:
Marc opened a pizza box. Inside there was 3/4 of a pizza. Marc ate 1/2 of what was in the box. How much pizza did Marc eat?
Answer: he ate 3/8
Janice is preparing a recipe that calls for 3/4 of a cup of oil per serving. If Janice needs to prepare 2 and 2/3 servings, how many cups of oil will she need?
1 serving: 3/4
She will need 2 cups
Different denominators
4,8,12,16,20,24,28,32,
6,12,18,24,30,36
1/4*6 + 1/6*4
6/24+4/24 =10/24=5/12
What is a fraction?
Even if you do use the LCM to find a common denominator, it still won’t give you the simplest form for the answer.
Dividing a fraction
Leave it, change it, flip it.
Prime factorization is used to find the LCM
24: 1,2,3,4,6,8,12,24
24=2*2*2*3
24=2^3*3
GCF
36=2*2*3*3
What is the GCF of 24 and 36?
24=2*2*2*3
36=2*2*3*3
GCF=2*2*3=12
List method of GCF
24: 1,2,3,4,6,8,12,24
36: 1,2,3,4,6,9,12,18,36
GCF=12
List Method of LCM
24: 24,48,72
36: 36,72
LCM=72
When we say a is divisible by b, if another number c
cxb=a
Example: 24 is divisible by 2 because there is another number that will be multiplied by 2 to get 24.
10 is divisible by 5
5 divides 10
5 is a divisor of 10
10 is a multiple of 5
5 and 2 are factors of 10
Ending of a number: by 2, 5, 10
Find sum of number: by 3, 6, 9
Last two digits: by 4
Last three digits: by 8
Double the last number: by 7
Chop off: by 11