CBSE Class 3 Mathematics — Flashcards for Quick Revision

A: They made marks on the wall - one mark for each cow going out, then struck out one mark for each cow coming back home. This helped them know if any cows were missing.

A: You can: 1) Make marks or tallies, 2) Use stones or tokens, 3) Match each object with something else (like fingers), 4) Group them in sets, 5) Draw pictures or symbols for each object.

A: They were worried because the marks showed that 2 cows had not returned home. This meant 2 cows were missing and might be lost somewhere.

A: A cube is a 3D shape that has 6 square faces, all of the same size. All its edges are straight and equal in length. A dice is a good example of a cube.

A: A cuboid is a 3D shape that has 6 rectangular faces. It has straight edges and flat faces. A matchbox or a brick is a good example of a cuboid.

A: A cylinder is a 3D shape that has 2 flat circular faces (top and bottom) and 1 curved face around the sides. A bottle or a can is a good example of a cylinder.

A: The 10 symbols are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. These symbols were created by ancient Indians and are now used everywhere in the world to write any number, however large.

A: The symbol '0' means 'nothing' and it is what really made our number system work! Without 0, we couldn't write numbers like 10, 20, 100, 101, etc. It helps us show empty places in numbers.

A: 70 + 30 = 100. When we have 70, we need 30 more to make 100. This is called making number bonds to 100.