Slide things along a ruler, balance a scale, read a jug and a kitchen scale, and change between units. Play, solve missions and beat the clock.
Start here. To measure a length, line up one end of the object with the 0 on the ruler. Then read the number at the other end. A centimetre (cm) is a small step on the ruler. At the first level you can also count paper clips, to see why we need a standard unit: a long clip and a short clip would give different answers, but a centimetre is always the same size.
Half and halves. Most rulers also have a mark halfway between two centimetres. If the end of a pencil sits on that mark, it is a half centimetre longer, like 7½ cm. If an object does not start at 0, subtract: the right end minus the left end is the length. A pencil that goes from 3 to 8 is 8 − 3 = 5 cm long. One metre (m) is 100 cm.
Weight. A balance scale is level when both sides weigh the same. Add up the little weights on one side to find how heavy the bag on the other side is. A kitchen scale dial shows grams (g). One kilogram (kg) is 1000 g, so one full turn of our dial is 1 kg.
Capacity. A measuring jug shows how much liquid it holds in millilitres (mL). One litre (L) is 1000 mL. Read the line that the top of the water touches.
Changing units. Going from a big unit to a small unit gives a bigger number: 3 m is 300 cm. Going from small to big gives a smaller number: 4000 g is 4 kg. Perimeter is the distance around a shape: add all the sides. If you like inches: 1 inch is about 2.5 cm.
Try this above. In Play, slide the pencil so its left end is not on 0 and read both ends. Then slide it to 0. Balance the scale with different weights. Move the jug slider to 1000 mL and see what happens.
The 0 mark is where counting begins. If you start at another mark, you have to subtract the starting number from the end number. Starting at 0 means the number at the end is already the length.
There are 100 cm in 1 m. So 2 m is 200 cm, and 300 cm is 3 m.
In everyday language we say weight. A kitchen scale shows how much matter is in something, in grams and kilograms. This game uses the everyday word weight.
Pick the level, not the age. "Just starting" compares lengths and measures in clips and whole centimetres. "I know the basics" uses half centimetres, objects that do not start at 0, and a balance scale. "Challenge me" adds reading a jug and a kitchen scale, converting units and perimeter.
No. It is free and needs no account. Your stars are saved in your own browser.