Mental Math
80 x 30 = ?
2400
3x + 5 = 11
What is x?
x = 2
A jacket costs 80$. It is on a sale with a 25% discount. How much money do you save, and what is the sale price of the jacket?
Saved money = $20
Sale price = $60
Triangle ABC and triangle DEF are congruent.
If angle A = 50 °, angle B = 60 °, and side AB = 8cm, what are the measures of the corresponding angles and the side of DE in triangle DEF?
Angle A = Angle D - 50o
Angle B = Angle E - 60o
Angle C = Angle F - 70o
Side AB = Side DE - 8cm(-2) x 12 = ?
-24
480/40 = ?
12
6x + 3 = 9 x 3
What is x?
4
A school has 200 students. If 15% of the students are absent one day, how many students are absent?
30 students are absent.
Triangle PQR and triangle STU are congruent.
If side PQ is 7cm, side QR is 9cm, and angle R is 40o.
What is the length of side ST, and what is the angle of U?
Side ST = Side PQ - 7cm
Angle T = Angle R - 40o
-15 / (-3) = ?
5
360 x 9 = ?
3240
If y = 6
24 x y = ?
144
A store increases the price of a bicycle from $150 to $180.
What is the percentage increase of the bicycle?
The price is increased by 20%.
Triangle XYZ and ABC are congruent.
Triangles XYZ and ABC are congruent.
Side XY = 12 cm, Side YZ = 9 cm, Angle Y = 70°, Side AB = 12 cm, Angle B = 70°
If side BC = 15 cm, what is the length of side XZ and the measure of angle Z in triangle XYZ?
angle Z = 70°, this is a congruent angle with angle B.
Side XZ = AC
Greg lives near the ocean. One evening the temperature gets colder by an average of -3oC every two hours. Determine the change in temperature after six hours.
-9oC
320/8 = ?
40
If y = 8
y2 + 10 = ?
74
A smartphone originally costs $400. Its price is reduced to $320 during a sale.
What is the percentage decrease in the smartphone?
The price is decreased by 20%.
In the figure, triangle DEF is congruent to triangle GHI.
Side DE = 8 cm, Side EF = 6 cm, Angle D = 50°, Side GH = 8 cm, Angle H = 50°
If side HI = 10 cm, what is the measure of angle E?
angle E = 9
A submarine dives at an average of 16 meters per minute for 8 minutes. How far does the submarine dive?
128 meters
9362/24 = ?
41.3 (recurring)
2(3x - 4) + 5 = 4x + 7
What is x?
x = 5
If Tom had a 5L water bottle, and in 19 hours, he finished 32% of it.
How many liters did he finish in one hour?
0.0842 liters
In triangles ABC and DEF, it is given that:
△ABC≅△DEF\triangle ABC \cong \triangle DEF△ABC≅△DEF
Angle A = 45°, Angle B = 65°, Side AB = 8 cm, and Side BC = 10 cm.
Using the properties of congruent triangles, find the following:
The measure of angle C in triangle ABC.
The length of side DE in triangle DEF.
The measure of angle D in triangle DEF.
Angle C = 70°
Side DE = 8 cm
Angle D = 45°
2(-3 + 4) - 15 = ?
-13