Mastering Proportions with Mental Math Techniques

The video tutorial covers solving ratios using mental math and cross products. It begins with simple mental math techniques to find equivalent fractions and solve for unknowns. The tutorial then progresses to using cross products for more complex problems, including those requiring a calculator. Finally, it introduces advanced challenges involving the distributive property, encouraging students to apply learned methods to solve equations. The session ends with a prompt for students to prepare for story problems in the next lesson.

What is the value of Z if 7/12 is equivalent to 21/36?

• 8

• 7

• 6

• 5

Tags

CCSS.4.NF.A.1

CCSS.3.NF.A.3B

CCSS.3.NF.A.3A

If 8 times 3 is 24, what is the value of B in the proportion 3/B = 8/24?

• 8

• 7

• 6

• 9

Tags

CCSS.7.RP.A.2C

What is the value of M if 5/40 is equivalent to M/16?

• 2

• 3

• 4

• 5

Tags

CCSS.4.NF.A.1

CCSS.3.NF.A.3A

CCSS.3.NF.A.3B

In the proportion 15/5 = 30/P, what is the value of P?

• 20

• 15

• 10

• 5

Tags

CCSS.7.RP.A.2B

What is the first step in solving proportions using cross products?

• Divide across

• Multiply across

• Subtract the ratios

• Add the ratios

If 25X = 570, what is the value of X?

• 25.8

• 24.8

• 23.8

• 22.8

Tags

CCSS.6.NS.B.2

CCSS.5.NBT.B.6

In the proportion 21/15 = X/12, what is the value of X?

• 17.8

• 14.8

• 15.8

• 16.8

Tags

CCSS.7.RP.A.2B

What is the value of D if 3D = 816?

• 273.2

• 272.2

• 271.2

• 270.2

Tags

CCSS.6.EE.B.7

In the equation 42 = 9(B - 1), what is the value of B?

• 7.6

• 4.6

• 5.6

• 6.6

Tags

CCSS.7.EE.B.4A

If 8 = 8(M - 8), what is the value of M?

• 10

• 9

• 8

• 7