Take Away Subtraction Model

Now let s see what happens when we subtract one positive and one negative number.

Take away subtraction model. Adding a neutral pair does not change the value. Recall familiar problems such as if harry had 30 marbles and 10 were taken away by his friend ron how many were left in symbol form that problem would be 30 10 20 which might have been read as 30 take away 20. Model subtraction of whole numbers. Take away problems are just what the approach says removing or taking away items or an amount from a given set of items or amount.

The take away model of subtraction is the model that is most familiar from elementary school. Let s start by modeling the subtraction expression we just considered latex 7 3 latex. When we use counters we can think of subtraction the same way. If given two amounts or sets of items a comparison could be made between them which leads to the next approach.

Remember a block represents 1 and a rod represents 10. Each example used counters of only one color and the take away model of subtraction was easy to apply. We will continue to use counters to model subtraction. Take away comparison and missing addend.

A model can help us visualize the process of subtraction much as it did with addition. Subtraction has three approaches. Perhaps when you were younger you read 5 3 5 3 as five take away three. Again we will use latex text base 10 latex blocks.