Our Year 4 Math group linked World Ocean Day to learning Maths facts today.
OCEAN FACT #1 Over ¾ of our planet is covered by oceans
Math fun facts:
~ As a percentage, ¾ is 75%
~ As a decimal, ¾ is 0.75
~ As money, 75 cents
~ As a fraction, ¾ can also be written as: 6/8, 9/12, 12/16, 15/20, 18/24, 21/28, 24/32, 27/36, 30/40
We call these equivalent fractions. This means that they are all worth the same value – even though they look different!
How did we find them? We multiplied the top number (numerator) by two and then we did the same to the bottom number (denominator) and got 6/8. Then we multiplied the numerator by three and did the same to the denominator and got 9/12. We went on with this pattern 10 times. Finally, we discovered that if we took the zero off 30/40 it is the same as ¾!
MORE OCEAN FACTS
- Oceans are over-fished causing serious problems
- 90% of large fish such as tuna and cod are gone
Math fun facts:
~ As a decimal 90% is 0.9
~ As a fraction 90% is 9/10
We used our knowledge of our 9 times table to do some fraction patterns and we found that the denominator (remember that is the bottom number – d for down below) went up in 10’s:
9/10, 18/20, 27/30, 36/40, 45/50, 54/60, 63/70, 72/80, 81/90, 90/100
Again, if we took the zero off the 90/100, it brought us right back to 9/10.
We noticed again that these are all equivalent fractions, they are all worth the same value – even though they look different!
If 90% of the big fish are gone, this means that there are now only 10%, that’s like only having one of our ten fingers left after having 10.
Fortunately there are many more than 10 fish left in the ocean, but we decided that we really needed to think about overfishing the ocean as a serious problem.
We enjoyed our lesson so much, that we’ll be carrying on with our mathematical ocean research next week!
We think our Year 4 Mathematicians are all SUPER STAR(fish) – and our teachers, Ms Alison and Mrs Stef are not SEL(fish) when it comes to helping us to learn!
Why don’t you try to see what Maths facts you can find for the following ocean facts:
- Oceans contain 80% of all life on Earth
- In 1900 our oceans contained at least 6 times more fish than 2009.
Try to include some multiplication AND division facts!
And for those of you seeking a super challenge…The Pacific Ocean covers about 1/3 of Earth’s surface, and the Atlantic Ocean covers about 1/5. What fractional part of Earth’s surface is covered by these two oceans? (Hint: You will need to know or learn how to add fractions which have
different denominators by a common denominator.)