When Year 7 students try to change units, they often make some common mistakes. Here are some important things to look out for:

1. Forgetting the Conversion Factor: One of the biggest mistakes is not remembering the right conversion factor. For example, when changing centimeters to meters, keep in mind that 1 meter equals 100 centimeters. So, if you want to convert 250 cm to meters, you divide by 100:

   $$250 \text{ cm} \div 100 = 2.5 \text{ m}$$

2. Mixing Up Units: Be careful not to mix up similar units. For instance, confusing kilograms (kg) with grams (g) can lead to problems. There are 1000 grams in one kilogram. So, if you have 3 kg, remember to multiply by 1000 to change it to grams:

   $$3 \text{ kg} \times 1000 = 3000 \text{ g}$$

3. Not Keeping Track of Units: Always pay attention to the units you are using in your calculations. It helps to write out the units when you convert. For example:

   • Start: $250 \text{ cm}$
   • Convert: $250 \text{ cm} \div 100 = 2.5 \text{ m}$.

By avoiding these mistakes and practicing regularly, you will feel more confident when converting units!