Adding two-digit numbers up to 100 using tens and ones. Your child lines the numbers up, adds ones to ones and tens to tens, and makes a new ten when needed.
Add the ones, then the tens. If the ones make 10 or more, make a new ten and add it to the tens: 55 + 9 is 5 tens and 14 ones, which is 64.
tensgroups of ten
onessingle units, less than a ten
make a tentrade 10 ones for 1 ten
sumthe answer when you add
Watch for: Adding a one-digit number to the tens: 60 + 4 = 100. Writing 14 ones as “14” in the ones place instead of making a ten. Forgetting the new ten, so 55 + 9 = 54.
At home: Bundle straws or sticks in tens with rubber bands. Build 38 and 25, then put them together and bundle any 10 loose ones.
Sample sheet and answer key
Freddie's Frog Pond
Grade 1 · Adding within 100 · 1.NBT.C.4
NameDate
Freddie the frog lives in a busy pond full of bugs, lily pads and friends. Solve each problem to help Freddie out!
Warm-up: add tens
Count on by tens.
10 + 70 =30 + 10 =20 + 40 =40 + 30 =
Line them up
Tens under tens, ones under ones. Carry a ten when the ones make 10 or more.
1
24+8
2
50+40
3
69+2
4
58+2
5
74+5
Riddle time
Solve each one, then use the code to answer the riddle.
New problems every time, three levels (gentle, core and stretch), themes to pick from, a second page if you want one. Each sheet comes with an answer key and a one-page guide for grown-ups.
