Adding 10ths and 100ths math worksheet with 20 problems and answer column.

Let’s solve each problem step by step. We’re adding fractions with denominators of 10 and 100. To add them, we need to make the denominators the same — usually convert the tenths (denominator 10) into hundredths (denominator 100).

Remember:
To convert a fraction like \(\frac{a}{10}\) to hundredths, multiply numerator and denominator by 10 → \(\frac{a \times 10}{100} = \frac{10a}{100}\)

Then just add the numerators and keep denominator 100.

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Problem 1: \(\frac{4}{100} + \frac{8}{10}\)
Convert \(\frac{8}{10}\) → \(\frac{80}{100}\)
Add: \(\frac{4}{100} + \frac{80}{100} = \frac{84}{100}\)

Problem 2: \(\frac{11}{100} + \frac{6}{10}\)
\(\frac{6}{10} = \frac{60}{100}\)
Add: \(\frac{11}{100} + \frac{60}{100} = \frac{71}{100}\)

Problem 3: \(\frac{12}{100} + \frac{2}{10}\)
\(\frac{2}{10} = \frac{20}{100}\)
Add: \(\frac{12}{100} + \frac{20}{100} = \frac{32}{100}\)

Problem 4: \(\frac{63}{100} + \frac{1}{10}\)
\(\frac{1}{10} = \frac{10}{100}\)
Add: \(\frac{63}{100} + \frac{10}{100} = \frac{73}{100}\)

Problem 5: \(\frac{2}{10} + \frac{78}{100}\)
\(\frac{2}{10} = \frac{20}{100}\)
Add: \(\frac{20}{100} + \frac{78}{100} = \frac{98}{100}\)

Problem 6: \(\frac{3}{10} + \frac{51}{100}\)
\(\frac{3}{10} = \frac{30}{100}\)
Add: \(\frac{30}{100} + \frac{51}{100} = \frac{81}{100}\)

Problem 7: \(\frac{3}{10} + \frac{61}{100}\)
\(\frac{3}{10} = \frac{30}{100}\)
Add: \(\frac{30}{100} + \frac{61}{100} = \frac{91}{100}\)

Problem 8: \(\frac{11}{100} + \frac{8}{10}\)
\(\frac{8}{10} = \frac{80}{100}\)
Add: \(\frac{11}{100} + \frac{80}{100} = \frac{91}{100}\)

Problem 9: \(\frac{1}{100} + \frac{4}{10}\)
\(\frac{4}{10} = \frac{40}{100}\)
Add: \(\frac{1}{100} + \frac{40}{100} = \frac{41}{100}\)

Problem 10: \(\frac{4}{10} + \frac{47}{100}\)
\(\frac{4}{10} = \frac{40}{100}\)
Add: \(\frac{40}{100} + \frac{47}{100} = \frac{87}{100}\)

Problem 11: \(\frac{21}{100} + \frac{6}{10}\)
\(\frac{6}{10} = \frac{60}{100}\)
Add: \(\frac{21}{100} + \frac{60}{100} = \frac{81}{100}\)

Problem 12: \(\frac{5}{10} + \frac{38}{100}\)
\(\frac{5}{10} = \frac{50}{100}\)
Add: \(\frac{50}{100} + \frac{38}{100} = \frac{88}{100}\)

Problem 13: \(\frac{7}{10} + \frac{18}{100}\)
\(\frac{7}{10} = \frac{70}{100}\)
Add: \(\frac{70}{100} + \frac{18}{100} = \frac{88}{100}\)

Problem 14: \(\frac{3}{10} + \frac{33}{100}\)
\(\frac{3}{10} = \frac{30}{100}\)
Add: \(\frac{30}{100} + \frac{33}{100} = \frac{63}{100}\)

Problem 15: \(\frac{2}{100} + \frac{3}{10}\)
\(\frac{3}{10} = \frac{30}{100}\)
Add: \(\frac{2}{100} + \frac{30}{100} = \frac{32}{100}\)

Problem 16: \(\frac{6}{10} + \frac{33}{100}\)
\(\frac{6}{10} = \frac{60}{100}\)
Add: \(\frac{60}{100} + \frac{33}{100} = \frac{93}{100}\)

Problem 17: \(\frac{8}{100} + \frac{5}{10}\)
\(\frac{5}{10} = \frac{50}{100}\)
Add: \(\frac{8}{100} + \frac{50}{100} = \frac{58}{100}\)

Problem 18: \(\frac{4}{10} + \frac{32}{100}\)
\(\frac{4}{10} = \frac{40}{100}\)
Add: \(\frac{40}{100} + \frac{32}{100} = \frac{72}{100}\)

Problem 19: \(\frac{5}{10} + \frac{28}{100}\)
\(\frac{5}{10} = \frac{50}{100}\)
Add: \(\frac{50}{100} + \frac{28}{100} = \frac{78}{100}\)

Problem 20: \(\frac{15}{100} + \frac{4}{10}\)
\(\frac{4}{10} = \frac{40}{100}\)
Add: \(\frac{15}{100} + \frac{40}{100} = \frac{55}{100}\)

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Final Answer:
1. 84/100
2. 71/100
3. 32/100
4. 73/100
5. 98/100
6. 81/100
7. 91/100
8. 91/100
9. 41/100
10. 87/100
11. 81/100
12. 88/100
13. 88/100
14. 63/100
15. 32/100
16. 93/100
17. 58/100
18. 72/100
19. 78/100
20. 55/100