10 hundredths make 1 tenth. Rename tenths as hundredths before adding.
Worked example
9/10 = ?/100
Answer:90
10 hundredths make 1 tenth. Multiply the top and the bottom by 10: 9/10 = 90/100. The missing top is 90. Answer: 90.
For grown-ups: Tenths ↔ hundredths (3/10 = 30/100). Below: three problems to try with the worked answers, and a free printable sheet. Children can practise the same skill as a game, with no sign-up and no ads.
CCSS 4.NF.C.5
What this practises, for teachers
Practices tenths ↔ hundredths (3/10 = 30/100) (4.NF.C.5). A printable sheet with its answer key, worked answers on the page, no accounts.