Expression of a variable from the formula - 7th grade (12y) - math problems

Number of problems found: 238

  • Two thirds
    fractions_10 Find two-thirds of the number equal to two-thirds of 99
  • Simple sequence
    sequence_geo_6 Continue with this series of numbers: 1792,448, 112, _, _
  • Radius
    green_circle Determine the radius of the circle, if its perimeter and area is the same number.
  • Sum of four numbers
    seq_6 The sum of four consecutive natural numbers is 114. Find them.
  • Cross five
    5squares2 The figure on the picture is composed of the same squares and has a content of 45cm². What's its perimeter?
  • Greg and Bill
    Clock0400_12 Greg is 18 years old. He is 6 less than 4 times Bill's age. How old is Bill?
  • Car and cyclist
    cyclist_6 Cyclist started from town at speed 18 km/h. After 1 hour 30 min started the car from town and caught up with the cyclist in 50 minutes. How fast was a car?
  • Interior angles
    triangles_1 Calculate the interior angles of a triangle that are in the ratio 2: 3: 4.
  • One and a half chicken
    chicken_1 One and a half chicken bears one and a half egg in one and a half day. How many eggs can withstand from 6 chicken in 6 days?
  • Circle chord
    circles_6 Calculate the length of the chord of the circle with radius r = 10 cm, length of which is equal to the distance from the center of the circle.
  • Volume of sphere
    sphere_in_cube How many times does the volume of a sphere increase if its radius increases 2 ×?
  • Find the
    kruh Find the radius of the circular base of the vessel, whose perimeter is 2.51 m. Write the result to one decimal place in meters. Via the π sign - Ludolph's number
  • Cube edge
    cubes_9 Determine the edges of the cube when the surface is equal to 37.5 cm square.
  • Cone from cube
    cones The largest possible cone was turned from a 20 cm high wooden cube. Calculate its weight if you know that the density of wood was 850 kg/m3
  • Cube edges
    cube_shield_3 The sum of the lengths of the cube edges is 42 cm. Calculate the surface of the cube.
  • Twice of radius
    gule How many times does the surface of a sphere decrease if we reduce its radius twice?
  • Unknown number 24
    numbs_6 f we add 20, we get 50% of its triple. What is this unknown number?
  • Alley
    stromy_6 Alley measured a meters. At the beginning and end are planted poplar. How many we must plant poplars to get the distance between the poplars 15 meters?
  • Diameter
    circles2_1 What is the inside diameter of the cylinder container and if half a liter of water reaches a height 15 cm?
  • Raspberries
    maliny_2 Dano had 20 raspberries. John had 90% more raspberries than Dano. Determine how many raspberries have Dano and Juraj together.

Do you have an interesting mathematical word problem that you can't solve it? Submit a math problem, and we can try to solve it.

We will send a solution to your e-mail address. Solved examples are also published here. Please enter the e-mail correctly and check whether you don't have a full mailbox.

Please do not submit problems from current active competitions such as Mathematical Olympiad, correspondence seminars etc...