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Grade 1 (age 6-7)

grade 1 Numbers up to 100

Counting to Hundred

Ten groups of ten make one hundred, and a hundred is quite a big number, far more than the children in one class. When you lay the numbers 1 to 100 in a hundred grid, going down adds ten and going across adds one. Numbers that pair up evenly are even, and those with one left over are odd, which you can tell just from the last digit. Pick a number on the grid with the slider and find where it sits on the number line.

How big is 100?

🏫 What is 100?
①30 classmates together make 30
②All the students in a school together are often more than 100
③10 groups of 10 make 100

The hundred chart

25
💡 Patterns in the hundred chart
①Going one row down adds 10
②Going one square to the right adds 1
③Up to the number you pick, odd squares are green and even squares are blue
④That is why green and blue take turns, one square at a time
⑤Even numbers end in 0, 2, 4, 6, or 8

Numbers on a number line

50
📏 Reading a number line
①On a number line, numbers get bigger as you go right
②The tick marks split 0 to 100 into steps of 10
③50 sits exactly halfway between 0 and 100
④The orange dot marks where your number is

Even and odd numbers

👫 What are even and odd numbers?
①If you can make pairs with nothing left over, the number is even
②If one is left over, the number is odd
③Even: 2, 4, 6, 8, 10, 12
④Odd: 1, 3, 5, 7, 9, 11
⑤A number ending in 0, 2, 4, 6, or 8 is even

Wrap-up

Making 100
10 tens = 100
10 groups of 10 make 100
Even and odd
even: ends in 0,2,4,6,8 / odd: ends in 1,3,5,7,9
Pairs with none left over: even; one left over: odd
Number order
0 < 50 < 100
Numbers get bigger to the right. The symbol < means the left side is smaller
🎯 Remember
①The hundred chart shows number patterns
②Down adds 10, right adds 1
③Even numbers make pairs; odd numbers have one left over
④On a number line, the number farther right is bigger

Examples and unit check

Example 1
What number has 6 in the tens place and 3 in the ones place?
1
A 6 in the tens place stands for 60.
2
Add the 3 in the ones place: 60 + 3 = 63.
▸ 63
A two-digit number is (tens digit) × 10 + (ones digit).
Example 2
Find all the even numbers: 7, 10, 13, 24
1
A number is even if its last digit (the ones digit) is 0, 2, 4, 6, or 8.
2
7 ends in 7 (odd), 10 ends in 0 (even), 13 ends in 3 (odd), and 24 ends in 4 (even).
▸ 10, 24
Even numbers end in 0, 2, 4, 6, or 8.
Unit check
What number is 1 more than 99?
①98
②100
③90
④89
▸ ② 100
1
Find the number that comes right after 99.
2
99 + 1 = 100.
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