Level 1 · Ages 6–8
Imagine a big bag of marbles. To find out how many there are, you count them one by one: 1, 2, 3... But when there are lots of them, counting one by one takes forever. Mathematicians found a brilliant trick: making groups of 10.
A group of 10 is called a ten. If you have 3 groups of 10 marbles and 4 loose marbles, you have 34 marbles. The number 34 means exactly that: 3 tens and 4 units. The place of each digit matters a lot: in 34, the 3 counts as 30, while in 43, the 3 only counts as 3.
To compare two numbers, look at the tens first. The one with more tens is bigger. If they have the same number of tens, use the units to decide. We write the result with symbols: 52 > 25 reads "52 is greater than 25", and 25 < 52 reads "25 is less than 52". Handy trick: the pointy end of the symbol always points to the smaller number.
You can also picture a long line where all the numbers stand in order: 0, 1, 2, 3... The further a number is along that line, the bigger it is. Your turn to play!
Read it again any time, including while you work through the exercises.
Imagine a big bag of marbles. To find out how many there are, you count them one by one: 1, 2, 3... But when there are lots of them, counting one by one takes forever. Mathematicians found a brilliant trick: making groups of 10.
A group of 10 is called a ten. If you have 3 groups of 10 marbles and 4 loose marbles, you have 34 marbles. The number 34 means exactly that: 3 tens and 4 units. The place of each digit matters a lot: in 34, the 3 counts as 30, while in 43, the 3 only counts as 3.
To compare two numbers, look at the tens first. The one with more tens is bigger. If they have the same number of tens, use the units to decide. We write the result with symbols: 52 > 25 reads "52 is greater than 25", and 25 < 52 reads "25 is less than 52". Handy trick: the pointy end of the symbol always points to the smaller number.
You can also picture a long line where all the numbers stand in order: 0, 1, 2, 3... The further a number is along that line, the bigger it is. Your turn to play!
Compare 47 and 74. Which one is bigger?
47 = 4 dizaines + 7 unités
I break down 47: it contains 4 groups of 10.
74 = 7 dizaines + 4 unités
I break down 74: it contains 7 groups of 10.
7 > 4
I compare the tens first: 7 tens is more than 4 tens. No need to look at the units.
Result: 74 > 47