Step-by-step Maths Level 5: Adding fractions with the same denominator
Part of the Step-by-step Maths Level 5 adding and subtracting fractions with the same denominator chapter. Chapter overview · whole chapter on one page
Adding fractions with the same denominator
Add the top numbers. Keep the bottom number the same, because the parts are the same size: 2/8 + 3/8 = 5/8.
If the answer can be simplified, divide the top and bottom by the same number: 2/8 + 2/8 = 4/8 = 1/2.
Key ideas
- Add the top numbers; keep the bottom number.
- Simplify by dividing the top and bottom by the same number.
- Never add the bottom numbers.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.2 + 3 = 5
- Keep the bottom number 8. The total is counted in the same parts.5/8
- Write the answer. This is the simplest form.5/8
Check. Check: 5/8 is equal to 5/8.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.2 + 2 = 4
- Keep the bottom number 8. The total is counted in the same parts.4/8
- Simplify. Divide the top and bottom by the same number, which is 4.4/8 = 1/2
- Write the answer. This is the simplest form.1/2
Check. Check: 1/2 is equal to 4/8.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.3 + 4 = 7
- Keep the bottom number 10. The total is counted in the same parts.7/10
- Write the answer. This is the simplest form.7/10
Check. Check: 7/10 is equal to 7/10.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Watch out
Watch out. 2/8 + 3/8 is 5/8, not 5/16. The bottom number does not change when you add.
Exam tip
Grown-up tip. Ask the child: “Are the pieces the same size? If so, what changes when you add?”
Exercise 6B Practice: adding fractions
Non-calculatorMethod. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.5 + 1 = 6
- Keep the bottom number 8. The total is counted in the same parts.6/8
- Simplify. Divide the top and bottom by the same number, which is 2.6/8 = 3/4
- Write the answer. This is the simplest form.3/4
Check. Check: 3/4 is equal to 6/8.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.1 + 2 = 3
- Keep the bottom number 6. The total is counted in the same parts.3/6
- Simplify. Divide the top and bottom by the same number, which is 3.3/6 = 1/2
- Write the answer. This is the simplest form.1/2
Check. Check: 1/2 is equal to 3/6.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.2 + 2 = 4
- Keep the bottom number 5. The total is counted in the same parts.4/5
- Write the answer. This is the simplest form.4/5
Check. Check: 4/5 is equal to 4/5.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.3 + 1 = 4
- Keep the bottom number 6. The total is counted in the same parts.4/6
- Simplify. Divide the top and bottom by the same number, which is 2.4/6 = 2/3
- Write the answer. This is the simplest form.2/3
Check. Check: 2/3 is equal to 4/6.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.5 + 4 = 9
- Keep the bottom number 10. The total is counted in the same parts.9/10
- Write the answer. This is the simplest form.9/10
Check. Check: 9/10 is equal to 9/10.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.1 + 2 = 3
- Keep the bottom number 8. The total is counted in the same parts.3/8
- Write the answer. This is the simplest form.3/8
Check. Check: 3/8 is equal to 3/8.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.4 + 2 = 6
- Keep the bottom number 8. The total is counted in the same parts.6/8
- Simplify. Divide the top and bottom by the same number, which is 2.6/8 = 3/4
- Write the answer. This is the simplest form.3/4
Check. Check: 3/4 is equal to 6/8.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.2 + 1 = 3
- Keep the bottom number 4. The total is counted in the same parts.3/4
- Write the answer. This is the simplest form.3/4
Check. Check: 3/4 is equal to 3/4.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.1 + 1 = 2
- Keep the bottom number 4. The total is counted in the same parts.2/4
- Simplify. Divide the top and bottom by the same number, which is 2.2/4 = 1/2
- Write the answer. This is the simplest form.1/2
Check. Check: 1/2 is equal to 2/4.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.3 + 1 = 4
- Keep the bottom number 5. The total is counted in the same parts.4/5
- Write the answer. This is the simplest form.4/5
Check. Check: 4/5 is equal to 4/5.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.2 + 1 = 3
- Keep the bottom number 5. The total is counted in the same parts.3/5
- Write the answer. This is the simplest form.3/5
Check. Check: 3/5 is equal to 3/5.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.1 + 3 = 4
- Keep the bottom number 5. The total is counted in the same parts.4/5
- Write the answer. This is the simplest form.4/5
Check. Check: 4/5 is equal to 4/5.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.1 + 2 = 3
- Keep the bottom number 4. The total is counted in the same parts.3/4
- Write the answer. This is the simplest form.3/4
Check. Check: 3/4 is equal to 3/4.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.4 + 1 = 5
- Keep the bottom number 6. The total is counted in the same parts.5/6
- Write the answer. This is the simplest form.5/6
Check. Check: 5/6 is equal to 5/6.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.2 + 2 = 4
- Keep the bottom number 6. The total is counted in the same parts.4/6
- Simplify. Divide the top and bottom by the same number, which is 2.4/6 = 2/3
- Write the answer. This is the simplest form.2/3
Check. Check: 2/3 is equal to 4/6.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.
Method. Add the top numbers and keep the bottom number. Simplify if you can.
- Add the top numbers. The bottom number stays the same, because the parts are the same size.6 + 1 = 7
- Keep the bottom number 10. The total is counted in the same parts.7/10
- Write the answer. This is the simplest form.7/10
Check. Check: 7/10 is equal to 7/10.
Watch out. Do not add the bottom numbers too. 2/8 + 3/8 is 5/8, not 5/16.