Parents ask us constantly what they should be doing at home. The honest answer is: much less than you fear, but much more consistently than you are probably managing.
Ten minutes a day, at roughly the same time, beats an hour on Sunday every single time. Consistency is what builds the habit, and the habit is what does the work.
In those ten minutes, resist the urge to teach. Your job is not to explain fractions. Your job is to be interested. Ask what the hardest part was. Ask them to teach you something from today. Sit quietly while they read and let the silence do its job.
There is a short list of phrases worth retiring. "You're so clever" ties self-worth to a fixed trait, and a clever child who finds something hard concludes they must not be clever after all. "Just try harder" is heard as "you are not trying", which is rarely true. And finishing their sentence when they hesitate over a word removes exactly the struggle that builds the skill.
Replace them with process language. "That looked hard and you stayed with it." "How did you work that out?" "What would you try next time?" These sound small. Over a school year they are not small at all.
And when the ten minutes goes badly — because some days it will — end it early and warmly. A short good session tomorrow is worth far more than a long bad one tonight.