Question Video: Converting Masses from Kilograms to Grams

Video Transcript

Noah bought two and one-quarter
kilograms of carrots and four and one-quarter kilograms of apples. How many grams of food did he
buy?

Let’s begin this question by
writing the value of the kilograms of carrots and apples in a more mathematical
way. We’re told that the mass of carrots
is two and one-quarter, which we can write as the whole number two and a fraction of
one-quarter. The units of mass is the metric
unit of kilograms. Noah also bought four and
one-quarter kilograms of apples, so we can write that as four and one-quarter. We have the same units of
kilograms. We’re asked to work out how many
grams of food; that’s the total mass. We notice here that we’re asked in
terms of grams rather than kilograms. We can approach this in two
ways. We could either convert both of
these masses in kilograms into grams and then add. Or we could add them first and then
convert to grams.

Here, I’m going to add them
first. In order to add two and a quarter
and four and a quarter, we can add the whole numbers of two and four, giving us
six. We can then add a quarter and a
quarter, giving us two-quarters. But we can also simplify this
fraction to one-half, so we know that the total mass is six and a half
kilograms. We can recall that in one kilogram,
there’s 1000 grams. When it comes to converting six and
a half kilograms, it’s helpful to remember that the decimal form of this would be
6.5 kilograms. So we have 6.5, and we multiply it
by 1000 to find the mass in grams, which is 6500 grams. And so we’ve answered the question
that Noah bought 6500 grams of food.