Decimals
PEMDAS
Solve for X
Challenge: Ratios
+/- fractions
100

12.25 plus 1.5

13.75

100

2 Γ— (3 + 4) + 5

  • 2 Γ— 7 = 14

  • Then:
    14 + 5 = 19

βœ… Answer: 19

100

x βˆ’ 4 + 2 = 9

Steps:

  1. Combine like terms on the left:
      x βˆ’ 2 = 9

  2. Add 2 to both sides:
      x = 11
    βœ… Answer: x = 11

100

The ratio of red balls to blue balls is 8:12. Simplify this ratio. 

Solution:
Divide both by 4 β†’ 8 Γ· 4 : 12 Γ· 4 = 2:3

100

1/3 + 1/4

Steps:
Common denominator = 12
4/12 + 3/12 = 7/12
Answer:
7/12

200

9.15 βˆ’ 3.8

5.35

200

(8 βˆ’ 3)Β²

Steps: (5)Β² = 25
βœ… Answer: 25

200

0.4x βˆ’ 1.2 = 2.8

Steps:

  1. Add 1.2 to both sides:
      0.4x = 4.0

  2. Divide both sides by 0.4:
      x = 10
    βœ… Answer: x = 10

200

The ratio of cats to dogs is 2:3. If there are 15 dogs, how many cats are there?

Solution:
Set up proportion:
2 / 3 = x / 15
Cross multiply: 3x = 2 Γ— 15 = 30
x = 30 Γ· 3 = 10 cats

200

5/6 - 1/8

Common denominator = 24
20/24 - 3/24 = 17/24
Answer:
17/24

300

3.75 Γ— 2.4

9.0

300

6 + 4 Γ— (2 + 1)

Steps: 6 + 4 Γ— 3 β†’ 6 + 12 = 18
βœ… Answer: 18

300

βˆ’2(x βˆ’ 5) + 3 = 1

Steps:

  1. Distribute: βˆ’2x + 10 + 3 = 1

  2. Combine like terms: βˆ’2x + 13 = 1

  3. Subtract 13: βˆ’2x = βˆ’12

  4. Divide by βˆ’2: x = 6
    βœ… Answer: x = 6

300

The ratio of red cars to blue cars is 4:7. If there are 28 blue cars, how many red cars are there?

Solution:
Set up proportion:
4 / 7 = x / 28
Cross multiply:
7x = 4 Γ— 28 = 112
Divide both sides by 7:
x = 112 Γ· 7 = 16

βœ… Answer: 16 red cars

300

6/8 - 1/3

Common denominator = 24
18/24 - 8/24 = 10/24
Simplify 10/24 β†’ 5/12
Answer:
5/12

400

12.5 Γ— 0.08

1.0

400

(12 Γ· 3) + 2Β² Γ— 3

4 + 4 Γ— 3 β†’ 4 + 12 = 16
βœ… Answer: 16

400

3(x + 4) = 2x + 18

Steps:

  1. Distribute left: 3x + 12 = 2x + 18

  2. Subtract 2x from both sides: x + 12 = 18

  3. Subtract 12: x = 6
    βœ… Answer: x = 6

400

The ratio of boys to girls in a class is 2:3. There are 25 students total. How many boys and girls are there?

Solution:
Total parts = 2 + 3 = 5
One part = 25 Γ· 5 = 5
Boys = 2 Γ— 5 = 10
Girls = 3 Γ— 5 = 15

400

3/4 + 2/6

Steps:
Common denominator = 12
(3/4) = 9/12
(2/6) = 4/12
Add: 9/12 + 4/12 = 13/12
Simplify: 13/12 = 1 1/12

Answer:
1 1/12

500

15.75 Γ· 1.5

10.5

500

18 Γ· (3 Γ— 2) + 5Β² βˆ’ (4 + 1)

  • 3 Γ— 2 = 6 β†’ 18 Γ· 6 = 3

  • 5Β² = 25

  • 4 + 1 = 5
    β†’ 3 + 25 βˆ’ 5 = 23

βœ… Answer: 23

500

4(x + 2) βˆ’ 3 = 2(2x + 5) βˆ’ 1


Steps:

  1. Distribute both sides:
     Left: 4x + 8 βˆ’ 3 = 4x + 5
     Right: 4x + 10 βˆ’ 1 = 4x + 9

  2. Simplify both sides:
     4x + 5 = 4x + 9

  3. Subtract 4x from both sides:
     5 = 9.   βœ… Answer: No solution

500

The ratio of cats to dogs in a shelter is 5:8. If there are 40 cats, how many dogs are there?

Solution:
Set up proportion:
5 / 8 = 40 / x
Cross multiply:
5x = 8 Γ— 40 = 320
Divide both sides by 5:
x = 320 Γ· 5 = 64

βœ… Answer: 64 dogs

500

4/8 + 3/6 - 1/3

Common denominator = 24
(4/8) = 12/24
(3/6) = 12/24
(1/3) = 8/24
Calculate: 12/24 + 12/24 - 8/24 = 16/24
Simplify 16/24:
Divide numerator and denominator by 8 β†’ 2/3
Answer:
2/3

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