7.11 Value of decimal expressions

Follow the order of operations by doing the brackets first, then the multiplication, then the subtraction.

Follow the order of operations by doing the multiplication first and then the addition.

To find 0.65\times 10 we can multiply the numbers without the decimal point.

Since 0.65\times 10 has two decimal places we insert the decimal point into our answer so that there are two decimal places: \begin{aligned} 0.65\times 10&=6.50 \\ &=6.5 \end{aligned}

Now we can add our answer to 8.5 using a vertical algorithm: \begin{array}{c} &&&{}^18&.&5 \\ &+&&6&.&5 \\ \hline &&1&5&.&0 \end{array} So we have:

Follow the order of operations and do the multiplications from left to right, and then the subtraction.

0.6 \times 8 has one decimal place. So first we can multiply the whole numbers to get 6\times 8 = 48 and now we can add a decimal point so that there is one decimal place to get: 0.6 \times 8=4.8

0.6 \times 4 also has one decimal place. So we can multiply the whole numbers to get 6\times 4 = 24 and now we can add a decimal point so that there is one decimal place to get: 0.6 \times 4=2.4

Now we can subtract our results using a vertical algorithm: \begin{array}{c} &&4&.&8 \\ &-&2&.&4 \\ \hline &&2&.&4 \\ \hline \end{array} So we have: