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Grade 1 (age 6-7)

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, the pattern shows at a glance: 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. Here you 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 is the number 30
②All students in school is over 100!
③Ten groups of ten → 100!
The 100 Grid
25
💡 Find Patterns in the 100 Grid!
①Going down adds 10
②Going right adds 1
③Green is odd, blue is even
④Even numbers end in 2, 4, 6, 8, 0
Numbers on a Number Line
50
📏 Reading a Number Line
①Numbers grow as you go right on the line
②50 is right in the middle of 0 and 100
③Divided into groups of 10
Even and Odd
👫 What are Even and Odd?
①If you can pair them up, it is even
②If one is left over, it is odd
③Even: 2, 4, 6, 8, 10, 12...
④Odd: 1, 3, 5, 7, 9, 11...
⑤If it ends in 0, 2, 4, 6, 8 → even!
Summary
Building 100
10 × 10 = 100
Ten groups of ten make 100
Even and Odd
Even: ends in 0,2,4,6,8 / Odd: ends in 1,3,5,7,9
Pair-able = even, one left over = odd
Order of Numbers
0 < 50 < 100
Bigger as you go right
🎯 Remember!
①Find rules using the 100 grid
②Down +10, right +1
③Even pairs up, odd has one left
④Right on the number line = bigger
⑤Great work up to 100! Next is addition!
Examples and Unit Test
Example 1
What number has 6 in the tens place and 3 in the ones place?
1
A 6 in the tens place means 60.
2
Adding 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 (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), 24 ends in 4 (even).
▸ 10, 24
Even numbers end in 0, 2, 4, 6, or 8.
Unit Test
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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Numbers up to 50
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Addition Basics