Week 3 of 8
Week 3
2nd Grade → 3rd Grade · Subtraction within 100 and Reading comprehension
Math
Subtraction Within 100
Two-digit subtraction that requires regrouping — 52 − 27. Middle of second grade. This is the skill most second graders struggle with longest.
The mistake to watch for. Subtracting the smaller digit from the larger in each column regardless of which is on top: 52 − 27 answered as 35, from 7 − 2 and 5 − 2.
How to help. Before solving, have your child circle any column where the top digit is smaller. Naming the regroup before doing it prevents the reflex.
A worked example
Try 52 − 27. You cannot take 7 ones from 2 ones, so regroup: 52 is 4 tens and 12 ones. Now 12 − 7 = 5 ones and 4 tens − 2 tens = 2 tens. The answer is 25.
Words for this week
- subtract
- To take one number away from another to find how many are left.
- regroup
- To trade 10 ones for 1 ten (or 1 ten for 10 ones) when you add or subtract.
- difference
- The answer you get when you subtract.
- ten
- The number 10, one more than nine.
- digit
- One of the ten number symbols 0 to 9. The number 47 has two digits.
Read this week
Stegosaurus
A short dinosaurs & fossils article from our Learn library, chosen for this reading level. Read it together, then ask your child to tell you one new thing they learned.