Word problems within 20
Read the problem, decide whether to add or subtract, and write an equation. Adding joins; subtracting takes away or compares.
Try it: 8 birds sit on a wire and 5 more land. How many birds are there now?
Show answer
13, because 8 + 5 = 13.
Fact families
Three numbers can make four related facts. For 3, 4, and 7: 3 + 4 = 7, 4 + 3 = 7, 7 − 3 = 4, and 7 − 4 = 3.
Try it: Write the fact family for 2, 5, and 7.
Show answer
2 + 5 = 7, 5 + 2 = 7, 7 − 2 = 5, 7 − 5 = 2.
Tens and ones
A two-digit number is made of tens and ones. 34 is 3 tens and 4 ones.
Try it: What number is 5 tens and 2 ones?
Show answer
52.
Comparing two-digit numbers
Compare the tens first. If the tens match, compare the ones. Use >, <, or =.
Try it: Compare 47 and 52.
Show answer
47 < 52, because 4 tens is less than 5 tens.