Search Results For “add and subtract multiples of 10 and 100”

Use a number line to count on and back across zero.

Work out the addition questions in your head and just write down the answers.

Revising adding and using the relationship between addition and subtraction.

Mental addition and subtraction using decimals to make a total of 1 or 10.

Adding and subtracting numbers that cross the thousands boundary: often ?counting on? is the best method.

Doubling 2-digit numbers and halving 3-digit numbers mentally.

Some people like to start doubling with the units, others like to start with the tens. It doesn?t matter as long as the method is fast and accurate.

When we are multiplying by a number ending in 5 we can double the number and halve the other number before multiplying (by a multiple of ten, making it easy).

We return to an important concept again: the relationship between multiplication and division.

Understanding and using factors of numbers can make mental multiplication easier.

Tips and hints on using a calculator, including negative numbers and recurring decimals.

Looking at the properties of cuboids, prisms and pyramids.